


Natur geht vor Lehre

by Meaka



Category: Shingeki no Kyojin | Attack on Titan
Genre: Alpha/Beta/Omega Dynamics, Anal Sex, Established Relationship, M/M, Mating Cycles/In Heat
Language: English
Status: In-Progress
Published: 2020-09-14
Updated: 2021-02-17
Packaged: 2021-03-07 07:40:19
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 7
Words: 30,616
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26469574
Author URL: https://archiveofourown.org/users/Meaka/pseuds/Meaka
Summary: When Levi suffers from an illness-induced fever, his alpha mate's body misreads the signal as something else, triggering off inconvenient and disastrous consequences for them mid-mission beyond the walls.
Relationships: Levi/Erwin Smith
Comments: 115
Kudos: 294





	1. Natur geht vor Lehre

**Author's Note:**

> Whelp I'm feeling all the feels after Chapter 132 and just needed to cheer myself up. No spoilers in this btw.
> 
> So this is a random 'if ABO dynamics existed in the canon world' fic and is set in an alternate universe to my Verbind fic. Maybe. I'm not sure. Smut to come. And biology. Probably too much. But, meh.
> 
> If there's enough interest I could consider doing a backstory to this. But it may just stay a series of oneshot-type thingies.
> 
> Thanks to photogiraffe77 for helping me brainstorm this one! Girl you are my snk eruri rock!

Whose fucking stupid idea had it been to agree to a mission in the middle of winter? Because in all seriousness, they deserved a slow and painful death. Even if it was his beloved Commander and mate. Which it in all likelihood was.

The small omega hunkered further down into himself on the saddle, drawing the hood up on his fur-lined, army-standard winter coat. He pulled the buff around his neck up to his nose, and drew the drawstrings tight on the hood, so all that were visible were angry grey eyes. Snow swirled all around the soldiers in formation, and had already settled heavily under the hooves of the horses, which seemed equally unimpressed at having to trudge through the snow. Located on the back of the outskirts of the long-range scouting formation, Levi was stationed out in the middle of nowhere, the next rider several hundred yards ahead. But even in the snow, Levi knew this route like the back of his hand and wouldn’t get lost between here and the stopover.

Levi shivered and pressed his legs tighter against the warmth of his mount's flanks. He’d been shivering since the day before, and he knew now that it was not merely from the coldness of the season. There was a soreness in his throat when he swallowed, and as the horse under him rolled it’s massive legs as it ploughed on through the drifts, every jostle and jolt was paining Levi’s joints. Usually horse riding did a bit of a number on the area between his legs, causing a bit of a mild ache for a few hours after, but never this sort of bone-deep discomfort in his hips and shoulders. The alpha males had it worse of course; some of them walked funny for days after a particularly long mission. Levi smirked as he imagined them enduring the suffering they themselves put their mates through after a heat cycle. Last time after his own heat cycle, Levi had barely been able to close his stiff legs after having them forced open around Erwin's broad hips for so long. At last when blondie had finally sated himself and left him alone, Levi had to try and ease them slowly back into performing useful tasks, such as flexing and walking and standing.

So focussed was he on the way his body ached and complained at him, that Levi failed to notice the glint of large eyes peering out from the forest beside them. In a movement that should have been far less swift than his own, a 40 metre abnormal titan leapt out from behind one of the giant redwoods and skidded a literal mountain of snow over him and his horse.

Despite the snow being pure powder, the avalanche was as heavy as if a tonne of bricks had landed on him. Unable to see, Levi could feel his horse struggle beneath him as it was crushed under the weight of it. It was hard to draw breath, and Levi began to scrabble at the snow to try and dig his way out. But where the snow contacted his warm hands, it briefly melted, only to completely refreeze into something resembling cement. Just as he was beginning to think he might suffocate, suddenly he was scooped up into an enormous hand and dangled by one leg over the open maw of the beast that had surprised him.

“Not a fucking chance!” Levi growled. 

Firing a red flare into the air, he clicked his ODM into gear; swinging a blade at a big finger, Levi managed to nimbly swing away. He rolled on the snow and set off again into the air, aiming for the nape of the neck. He easily took down the titan, but when he next landed, he felt his legs shake and give way. Dizziness rocked him, and he felt nauseated as his vision spun. Falling to his knees, he managed to fire a purple flare into the air before the world swam around him and then went black.

~~~~

From seemingly nowhere, a red flare had been fired. Then a minute later, purple smoke filled the air. At first when Erwin had seen the red flare near the very back of the formation, he assumed his mate would easily dispatch any threat. But the purple flare had surprised him. In fact, he was surprised at there being any active titans in these sorts of conditions.

The formation moved as one creature towards the distress signal. As they approached, it was clear that an absolutely gigantic titan had been felled. It steamed as it slowly dissolved into the white landscape.

“Commander!” One of the novices had dismounted and was turning over a fallen man. Eyes widening, Erwin saw that it was his mate lying face down in the snow. The snow around him was white, so he was unlikely to be bleeding out. 

“Bring him here,” Erwin stayed on his horse and allowed Levi to be passed up to sit in front of himself.

Giving Levi a quick inspection, Erwin saw to his relief that he was breathing and there were no obvious injuries or limbs sitting at odd angles. Levi’s scent was a bit off though, and his hands were freezing, in complete contrast to the heat radiating off him through his coat and face.

Was Levi in heat? Surely he wasn't due one yet? 

Burying his nose in Levi’s face (the only exposed part of him) and inhaling deeply, Erwin frowned. He didn’t smell like he was in heat, and whenever his mate was in a mating cycle, every part of Levi would be warm. During a heat his hot little hands would guide Erwin down on top of him, and manoeuvre his head so that his alpha's mouth was against the mating mark that adorned Levi’s burning neck. But currently, his hands were frozen and tinged with blue.

Erwin had noticed that Levi had been behaving clumsily and oddly for the last couple of days; he’d knocked into furniture while walking a few times, spilled some tea he’d been pouring and had fallen asleep in a meeting mid-conversation. It had caused several eyebrows to raise in the room, and Erwin had dismissed him and instructed him to rest. It was all very unlike Levi. Perhaps he was ailing for something, and this was a fever rather than heat.

“Levi?” Erwin tried to rouse him, “Levi, what happened?”

A groan gave Erwin some reassurance that the other man would be alright. Levi’s eyes flitted open, “W-what the-?”

“Everyone return to formation!” Erwin bellowed as the wind started to pick up again, “Onwards,”

Spurring his horse to return to the Commander’s position in the formation, Erwin kept one hand one the reins and the other around the shivering omega sitting sideways in front of him.

“F-fucking g-giant one jumped out of n-n-nowhere,” staccatoed breaths escaped as Levi's teeth chattered hard. 

“You didn’t see it?” Erwin asked, incredulous. The fact that Levi had lost his usually excellent situational awareness unsettled Erwin greatly. 

“N-no, I was t-t-too c-cold and everything fucking hurts, couldn’t f-focus,” Levi's whole body was shaking as he spoke. 

“You feel warm,” Now that Levi was pressed against him, Erwin could feel the warmth return to his own limbs from their shared heat.

"Ah-AaChoo!" Levi gave an adorable sneeze into Erwin's chest. 

"Gesundheit." 

“Th-thanks. The bastard p-pushed a pile of s-snow on me. Fucker l-l-lifted me out, b-but m-my horse still under there,”

If she was, she was dead. The avalanche created by the stealthy titan had a huge fistful of snow snatched out of it and it still looked huge. It was probably a lucky thing that the titan _had_ lifted Levi out, otherwise the formation in all likelihood would have continued on, only to find themselves down one of their most important members at the stopover.

Reflexively, Erwin’s arms wrapped more tightly around his little mate. Levi was the most important man in his life, and the most important man in humanity’s collective lives too. To leave him behind was simply impossible. For him to drown under twenty metres of snow, unthinkable. To never see or hold him again, unimaginable.

By the time they reached the stopover, Levi was still shivering, and Erwin had an uncomfortably timed erection. Even in his thirties they were still prone to pop out of nowhere, especially if his mate was in close proximity. But to have one now was just supremely bad timing. Erwin shifted on the saddle to see if he was just sitting badly, but nope. The bastard stayed determinedly hard. Luckily he had Levi to hide him as he swung off the saddle. Cradling his mate in his arms, he let another soldier stable his horse and headed in towards the area they would use as a san.

“Y-you c-can’t be serious,” Levi quirked a frosty eyebrow at him, “me nearly d-dying got you hard?”

“No," Erwin retorted, "it’s probably just because you were held against me. I can't help myself when you are so close.”

The doctor was setting up the san in one of the smaller rooms in the keep. Setting Levi down for a minute, Erwin knelt over by the hearth to help hide his erection and to stack wood on the fire. Soon the small room was warm and bright. And his pants felt far less tight.

“Fever, rigors, aches. I think it might be a flu.” The doctor wiped his hands as he spoke to his Commander, “Luckily I brought some feverfew, so I might be able to get his temperature down and reduce the aches somewhat. It it’s hard to tell what symptoms are from the illness and what’s related to getting buried under a tonne of snow.”

“I’ll be f-fine Erwin,” Levi waved a hand dismissively, “Go and eat.”

Swooping down and pecking Levi on one hot cheek, Erwin turned to leave, “I don’t want to leave, but I’ll be back once I’ve debriefed the officers.” He pulled off his cloak and set it on his mate. Erwin felt too warm to need it anyway.

Mike was waiting for him with the other squad leaders in the room they used for their meetings. A map was spread out and the others were already pointing at it and discussing tomorrow’s route.

“Erwin,” Mike stepped back from him, nostrils flaring, “You reek. When did you say your next rut was due?”

“I’m not due one for another two months.” Erwin tried to sniff his own armpit, detecting nothing himself. But the other alpha had a particularly good nose, and was not often mistaken. “It can’t be a rut. Levi isn’t in heat.”

It was going to seriously fuck things up if he went into rut in the middle of an important mission. Both himself and Levi would be taken out of action if the omega had a heat triggered by it. And the other man wasn’t well; how would his body tolerate a heat cycle? It always took a ferocious amount out of Levi; he would always lose weight and be pretty unwell for about a week after.

Moblit studied Erwin cautiously, “I think we need a contingency plan in case you become unfit to lead.”

Nodding, Mike took a step back, clearly feeling the effects of another alpha’s rut. “Agreed. By morning we should have a pretty good idea if you are going into one. But whatever happens with you, I don’t think it’s such a terrible idea to keep Levi behind. He’s clearly not well and may end up more of a liability than an asset.”

Running a hand through his blonde hair, Erwin sighed, “Fine. If there is no sign of a rut by morning, then I think it’s safe to say that it’s unlikely to happen. But _if_ it happens, Hanji will take command and continue on. Levi and I can remain here. Then you can stop back here as planned.”

Hanji looked scandalised at the idea, “What, and leave you two here alone? And vulnerable? As much as I like the sound of being in charge, I can’t say I feel comfortable leaving you both here alone in a mating cycle. At least let me leave a couple of betas here.”

It was a fair point. “Fine. How about von Meyer and Wagner?” They weren’t exactly novice corpsmen, but they weren’t vital to the success of the mission either.

“Alright it’s settled.” Hanji rubbed their hands together in glee, looking far too thrilled about the rotten timing, “I must say though Erwin, I rather hope Mike’s nose is correct. I’m looking forward to leading this mission now!”

“Well one day it might be you taking command for real, so it’s no bad thing to get a practice run.”

Hanji waved away his words, “Oh Erwin, not for a long time,”

~~~

It was getting toasty in the san. Having felt unbearably cold for most of the day, Levi now had to suffer through horrible hot flushes and he could feel the sweat lashing off his body. He would have given anything to pull off all his clothes; the fabric and the belts were suffocatingly tight and his skin felt over sensitised. He pulled Erwin’s cloak up and took a deep inhale, hoping the scent of his strong mate would calm him as it usually did. But it seemed to be having the opposite effect and Levi felt himself become more and more agitated.

“Is this feverfew shit working at all?” Levi snapped at the doctor, tugging at his own clothes and fanning himself, “I feel as if I’m being boiled alive now,”

“That can happen when a fever breaks,” the doctor put a hand to Levi’s head. Frowned. Then touched his chest and hands and feet. “Although you do feel over warm.”

“Levi-“ A visage of blonde hair and tight muscle appeared in the door, and Levi felt his cares about his body temperature melt away, “-I think I’m in rut.”

“For god’s sake Erwin!” Levi groaned, “Didn’t you know you were due one when you planned this shitty mission?”

“I’m not due one,” the Commander began taking off his jacket, “I don’t know where this has come from,”

“Uh, if I may?” the doctor piped up, “perhaps your body mistook your mate’s fever as a heat cycle?”

It didn’t seem entirely impossible.

Fucking alphas. As always assuming everything was an open invitation for sex.

“Erwin, if you put me in heat I swear I’m going to kill you for real this time,” growled the now scowling omega. “I am _so_ not feeling up to a heat cycle.”

“I’m not sure we have any choice,”

“What about the mission?”

“We will have to stay behind. Hanji will take command-“

Levi opened his mouth to protest, but Erwin put a hand up to silence him, “-and they will do a fine job I’m sure.”

Annoyed beyond measure at the dumb alpha, Levi growled, “And what if a titan decides to swing by here and we’re trapped in a fucking mating lock, huh? We can’t exactly disengage and defend ourselves.”

“They’ll leave a couple of betas behind. Hopefully they won’t mind the noise and smell.”

“Fucking great,” Levi pitched himself backwards and there was an audible thump as his head hit the stone floor. Lying spread eagle, Levi turned his head to avert his gaze from his mate. He tried to control his breathing, which was becoming ever more erratic, whether from fever, or heat or anger he wasn’t sure.

“I’ll, uh, just go somewhere else then,” the doctor said cheerily, “I’m sure you’ll want some privacy.”

“Thank you,” Erwin waved as the man departed. Then he closed the door with a slam and stripped off completely. Levi tried to not turn his head to watch, but failed. Stupid biology. Stupid alphas. Stupid Erwin.

He was still shaking his head when Erwin approached him and began tugging Levi’s clothes off too. And none too carefully.

Fixing Erwin’s blue gaze with his own, Levi growled, “I want these hung up, or they’re going to dry all wrinkly,”

“Hush,” Erwin doffed Levi’s cravat and placed a gentle kiss on their mating mark. Levi scowled. The bastard knew that kissing him there would melt away any resistance Levi tried to muster against his alpha. “Stop fretting about your uniform. It’ll be under your coat anyway.”

Laying there and refusing to help get himself undressed, Levi tried his best to glare hatefully at his mate. But the handsome smile on Erwin’s flushed face, and the glint of gold in his hair from the firelight wouldn’t allow the expression to reach Levi’s eyes.

One of Levi’s hands moved of it’s own accord and brushed the skin over Erwin’s heart; his alpha felt warm and strong. Instinctively Levi sniffed and caught a whiff of strong pheromones, fresh sweat and worn leather, ink and shirt starch.

 _FUCK ME,_ it screamed.

Levi felt himself grow slippery and wet from the slick escaping between his thighs, which parted to allow Erwin’s hips to fall naturally into the space between them.

Levi sighed. Ah well. There was no fighting it. Might as well enjoy it.


	2. 2

**Summary for the Chapter:**

> Erwin and Levi get busy! That's it. Maybe some feels.

**Notes for the Chapter:**

> I think it's best I give you all a fair warning for the fantasy biology I'm using. It's all made up and dumb. I hope you love it!

Face buried in between Levi’s legs, Erwin palmed himself gently to relieve some of the throbbing tension building in him. Licking up the slick where it wet Levi’s inner thighs, the alpha let his senses become saturated with the heady scent and taste of his lover; bronzed wood, tanned leather and Levi’s own intoxicating musk. Manly and potent and fertile. Erwin felt himself reduced to the primitive drives to protect and procreate with his gorgeous little mate.

He tongued sloppily at the tight entrance, looking forward to having his knot buried deep within Levi’s snug body.

Erwin’s rut didn’t usually have a head start on Levi’s heat; coupled with the fact that the omega’s body was reacting more sluggishly than normal, Erwin was deep into his rut long before his mate was ready for him.

“You’re going to have to control yourself,” Levi hissed as Erwin tried and failed to enter him again, “I’m not ready. Go and roll in the snow for an hour. Or ten.”

With supreme effort, Erwin dragged himself away and made to leave the room. A pair of pants hit his back on the way out.

“Dress you numbskull! You can’t march around with that thing on show,”

Although the pants didn’t exactly hide his erection, they gave the 13th Commander of the Survey Corps the chance to try and display some decency. As Erwin lay outside making hot, steamy snow angels on the white landscape, Mike emerged to have a smoke and watch him.

“Been kicked out?” The bigger alpha regarded him piteously. 

Erwin continued to stare up at the starry night sky, “He’s way behind me. I won’t fit without hurting him, and there’s no way I could knot him like this." Turning his head, he looked at the other blonde, "Have you come just to taunt me and watch me suffer?”

“I’m here to try and distract you. Want a smoke?”

“It might relax me.”

Mike stepped over and held out the box. Bumming a smoke, Erwin took a long drag and held it for a minute. He found smoking helped control his breathing when he was stressed. After a few inhales the nicotine worked it’s magic and he felt himself relax a bit.

“If I’m making things worse just tell me to leave.” The smell of another alpha wasn’t exactly what Erwin’s body wanted to detect at the moment with his omega in heat only yards away. But the snow helped him to rationalise the irrational.

Nodding, Erwin puffed out a smoke ring into the cold air, “I will. For now it’s fine.”

“This is shitty timing Erwin.”

Drawing a hand down his face, Erwin knew that there were going to be a lot of not very fun conversations happening after this expedition, “I don’t need reminded.”

“The brass are going to say that this is why omegas shouldn’t be in the military,”

“We both know the people would riot if Levi were discharged from our ranks,”

After a while, Mike headed back in to warm up. Erwin followed not long after and sat alone in a dark room; the rest of the corps wouldn’t have thanked him for stinking up the main chamber with the smell of his domination and rut.

For long hours he played with himself and managed to come a few times which took the edge off somewhat. But his body screamed at him to return to his mate and nibble at his neck, knot him and play with his soft cock. 

Mike’s blonde hair peered around the door a few hours later. “He smells fucking ripe. He’s at the very least close to being ready. I’d say you could go now. We’re making a move too. See you tomorrow or the next day.”

~~~

Levi wasn’t quite ready. He _was_ fucking horny, but anxiety from knowing he was unwell and lagging behind Erwin in their mating cycle seemed to have limited the amount of slick his body wanted to produce, and he told Erwin so, fearful of the pain.

“Then we’ll need to use the oil as well. Let me use my hand a bit too,”

“Yes to the oil. No to your hand.”

“Now who’s being irrational?”

“And I want face to face this time,” It was more comfortable and interesting to be stuck on a knot face to face than in doggy. Though Levi was sure Erwin would insist on mounting him from behind at least once.

Erwin pouted. Levi snarled under his breath--an honestly animal growl if you'd believe such a thing--and Erwin sighed. He moved back between Levi's thighs and grabbed the omega by the hips, fingers squeezing the sweet little ass, and lifted him up so they were now pressed together in Erwin's favourite way.

"Pants," Levi said.

"I don't want to wear my pants," Erwin retorted. It seemed downright unreasonable--

"The gear oil, moron. It's in my pants," Levi snapped. His weight was balancing all on his shoulders now from the position Erwin had him in.

"Oh." The blonde wiggled his fingers into the closest pants pocket he could find and plucked the almost empty bottle free of its tailored confines. He flicked the top off with his thumb, threw it over his shoulder, poured what was left in the bottle into his hand, and then tossed the empty container over his shoulder too. Levi watched him as he wrapped his hand around his own erection and pumped it, coating himself with the warm oil--warm since it had been sitting right up against Levi’s hips just moments ago. He had redressed at some point to go out and relieve himself, and left the pants on until Erwin had ripped them off again.

"Now, Erwin."

"Wait," he mumbled.

Levi was a terribly impatient lover: 'Lay down Erwin. Roll over Erwin. Stay still Erwin--I'm doing the work.'

“Now, Erwin.”

"Fiiine." He pulled Levi up with his unslicked hand, scooted closer on his knees, used his slippery fingers to get himself right against his favourite part of Levi's body--and then pushed in. Closed his eyes as he pushed past the tight ring of muscle and deep into Levi where everything was warm and snug and wonderful.

Levi groaned, wiggled, pressed his knees against Erwin's ribs, and squeezed him. Then the alpha began his slow and heavy thrusts. They both groaned in unison at finally being joined. Soon, the movement of Erwin’s hips increased in speed and power, and it became difficult to concentrate on anything. With the hardness buried so deep and fast inside of him, Levi couldn't hardly even breathe much less think.  
  
Impossible.  
  
Insane.

He felt the inexorable pull towards climax approaching; the rhythmic clenching around Erwin’s cock became stronger, until finally with one mighty contraction, his entrance clamped firmly shut around the base of the hardness within him. He could hear Erwin’s rumble of pleasure above him as his knot caught and rapidly filled with blood. It never failed to astonish Levi how big it could get. He’d witnessed it a few times first hand when Erwin had stimulated himself to one with his own hand, and Levi couldn’t quite believe something like that could actually fit inside him. He wasn’t even sure that he’d have let Erwin try to knot him during mating if he had seen it up close first.

Throwing his head back and shouting out as his body rocked itself through climax, Levi lost himself to the crisis of pleasure brought on by his own muscles squeezing around Erwin.

As the knot grew, stretching and stretching him, there was the usual shock of pain which stimulated ovulation. Or it would if Levi weren’t on a metric fuck tonne of industrial strength contraceptives. The discomfort was soon followed by more pleasure as his own body accommodated around the alpha’s girth.

There was another burst of pain as Erwin bit into his mating mark. Trapped in a mating lock with Erwin’s knot within him, and his sharp teeth buried in Levi’s neck, Levi instinctively wrapped his legs around Erwin’s waist and locked them at the ankles, pulling his mate further in.

They would be stuck like this for anywhere between half an hour and 75 minutes. As a young and virile alpha at the start of a rut, it would probably be on the longer end of the timescale. It was an extremely vulnerable time, and it had never felt more so than now when they were outside the walls with most of the corps miles away. Obviously when they would least want it to, the knot would long overstay it’s welcome. Once they’d been secretly fucking in a closet in a palace in-between two meetings, and Erwin hadn’t pulled out in time, resulting in them having to remain quiet in the cramped cupboard for over an hour waiting for the blasted thing to release. They had missed the second meeting, and it was quite clear from everyone’s expressions later on that they all knew exactly what had been going on for the Commander and the Captain to fail to be present at the same time.

“I can’t believe this is happening,” Levi sighed and stroked his hands through Erwin’s mussed locks, his alpha's knot still buried within him as they waited for the next series of contractions to start.

“Me neither.” Erwin’s deep voice soothed him somewhat, “I’m sure the others will be fine. I just hope it doesn’t last the full week,”

“Knowing our luck it will.” Ghosting his fingertips around Erwin’s lips, Levi smiled as his mate caught one playfully between his teeth and gave it a suck. “Do we have enough food if it does?”

“Only rations. Not that we ever manage to eat much anyway,”

“No.”

“But this time you aren’t well. So I don’t really know how it’s all going to pan out. You will need the food more than me.”

Not wanting to dwell on what _might_ happen right at this particular moment, Levi cupped the back of Erwin’s neck and initiated a deep kiss, as much for comfort as for lust of him.

Periodically they stopped their conversations and gentle touching as Levi’s body prepared once again to stimulate Erwin to ejaculate. It would start as a wave; first as a clenching near the omega’s entrance, then the muscles in his pelvic floor would flutter uncontrollably and finally it rolled up to the sheath containing the swollen knot inside him, bringing them both to climax

Erwin loved the feeling. His little mate would squirm and wriggle and shake uncontrollably as he spent himself, unable to talk or open his eyes during it. The blonde alpha rocked into the tight passage holding him firm; it felt like every drop was being milked from Erwin into the sheath around him. Nothing pleased the alpha more than knotting and filling his mate this way; knowing he was filling that little belly with his seed. Normal sex was fun, but heat-rut sex was his favourite.

Between them, Levi remained soft and dry. The knot within him pressed tightly against his internal blood vessels and urethra, preventing blood pooling in the omega’s cock and creating the inability to ejaculate. It was probably an evolutionary mechanism to avoid self-fertilisation back when omegas didn’t fire blanks the way they did now.

After over an hour of coming together over and over again, Erwin felt the death grip around the base of his cock loosen, and he softened and slipped out. Cum gushed out with him, but most remained inside. He planned to fill Levi up again later anyway.

With their urge to mate satiated for a while, the two cuddled and drank some water. A loud growl radiated from Erwin’s stomach. With a start, he realised that neither himself nor Levi had eaten in nearly twenty four hours.

“Are you hungry?”

“Not really. I’m tired. I’d rather sleep. Besides, what do we have to eat other than the rations?”

The rations were dry and gummy and tasteless. No one enjoyed them.

“Please try and eat some Levi,” he implored, then placed a hand on Levi’s head. With the demands of mating satisfied for at least another two hours, his mate should have returned to a semi-normal temperature. But his skin was still hot and sweaty. There was a slight shake as well that wasn’t entirely normal during heat. Sometimes Levi’s legs would shake from the aftershocks of orgasm or from the effort of locking them in place around Erwin, but this felt more like it was coming from Levi’s core muscles, “then I’ll make some more of that feverfew tea,”

“Gross. It tastes disgusting. But it does work, I suppose.” He pulled a blanket up over himself. Erwin frowned.

“Are you cold?” The fire was blazing and the room roasting.

“A bit.”

By the time Erwin had made the foul tasting tea, Levi was asleep. Although he felt loathe to wake him, it was best that he drank the tea when it was freshly brewed.

“Levi,” Erwin shook him slightly, earning a swat to the head.

“Not yet Erwin. Go play in the snow again.”

“No, it’s not that. Your tea is ready.”

“Eugh, fine.” Slurping it down noisily with a grimace, Levi handed him back the cup and lay down again. Snuggling in beside him, Erwin positioned himself as big spoon and tried to sleep.

~~

He awoke to Levi straddling him and his cock being guided into his mate. Slipping inside, Erwin canted his hips up and grasped Levi’s, holding him tight against him as he thrust up and in. This _was_ a nice way to be woken up. But his mattress felt terribly hard against his back. Then he remembered they were fucking on the floor in the keep, stuck out in the middle of Titan territory. If he hadn’t been in rut, Erwin was sure his cock would have softened immediately at the realisation.

Above him, Levi bounced beautifully on him. The veins on his neck were prominent as he sucked in breaths and rocked himself towards completion. The smell of his heat was overwhelming now, and Erwin found himself stroking Levi’s belly, wishing it would inflate one day with more than just his seed.

Maybe one day.

Soon he felt his mate's entrance grasp tightly around the base of his cock and Levi gasped with pain as the knot filled him. It always still amazed Erwin that it would fit in this tiny omega. Levi was quite the smallest omega man Erwin had ever met. Women were often this small, but they had proportionally bigger hips and pelvic outlets. The first time he had knotted Levi, he had torn horribly, and it had taken weeks to heal. He definitely would have torn again if they’d continued to try and copulate earlier in the night when Levi wasn’t yet fully in heat. Glad now that Levi had kicked him out at the time, Erwin allowed himself to enjoy the fruits of his patience.

Rolling them over so that he was on top- where he belonged- Erwin began to grind up against Levi’s prostate. As the clenching moved up from the base of his cock to surround and squeeze his sensitive head, Erwin roared out in pleasure as he came deep and hard, spurting hot essence into his mate.

His mind filled with images of his seed covering waiting eggs. But he knew rationally that there were none. Levi was meticulous with his contraception and took it religiously. They had agreed that pregnancy would be disastrous. Levi was so small that labour and delivery of a full term baby could theoretically kill him. And besides, he was too important on the battlefield to have him off duty for potentially up to two years during the pregnancy and then recovering afterwards.

Sometimes Erwin allowed himself to daydream about what more children of theirs might look like; who they would take after; what they would achieve with his brains and Levi’s martial prowess. Sometimes, he thought of one child in particular. During hormonal periods such as this, the thoughts could make him oddly weepy, so he only indulged in private. Not even Levi was privy to it.

Gyrating his hips, he tried to prolong his orgasm as long as he could. Once Levi had settled down again, Erwin relaxed his motion and stilled. Seeking solace, he wrapped his arms around his mate and licked at the scarred bite mark on Levi’s neck. It was a bit bruised and bloody from being bitten at repeatedly during their last round, and Erwin laved his tongue across it in a silent apology. Levi’s strong arms came up to hold him, and they lay together in silence, hearts beating against each other’s chests.

“You’re thinking too loudly,” Levi’s grey-blue eyes watched him curiously, “What are you thinking about?”

“Nothing,”

“It’s not ‘nothing’. When do _you_ ever think of ‘nothing’?”

“During rut. With my sexy mate.”

“Hmmm. Good answer.” Levi smirked at him, but then it faded, “You’re thinking about children again, aren’t you?”

Astonished at Levi’s insight, Erwin was unable to fully hide his shock even as he tried to shake his head in denial.

“You don’t fool me, Erwin. You can hide from the brass and all the others. But not me. Never from me. Besides-” Levi stretched out his legs from around his mate’s waist and then set his feet on the ground, knees bent and still spread around Erwin’s broad hips, “-it’s normal to think about it.”

Now he really was surprised, “Do you think about it?”

“Of course. I remember the first time I watched you stand and give that impressive speech to the nobles. You know, the one where half of them were in rapturous tears by the end and the other half were shitting bricks?”

“I know the one.” They hadn’t long been acquainted at that point, “What about it?”

“That’s when my body seemed to decide it wanted your babies.”

“Really?” Erwin hadn’t thought the speech had made that much of an impact on the newly recruited omega. In fact, Levi had looked bored and annoyed. He felt his cock spit out an unexpected load of cum at the thought of a teenaged Levi wanting his babies.

“Yeah. Then I saw your cock and wanted it too.”

It was nice to know that Levi wanted to make babies with him, but sad to know that it would never be.

Sighing, Erwin rolled them over again so he wasn’t crushing Levi, and the two lay together softly kissing and stroking skin.

The sun had risen a few hours ago. It was going to be a long day.

**Notes for the Chapter:**

> I implore other people to write these kind of fics. Because I want to read them. As much as I enjoy re-reading my own work, I would rather see where other people's minds take them on their own eruri journey's
> 
> THANK YOU FOR READING


	3. 3

**Summary for the Chapter:**

> Genuinely frightened now for his mate’s safety, Erwin felt sweat begin to bead on his own forehead, “Fuck, we need to get help,”
> 
> “No,” Levi pleaded weakly, “no please don’t let anyone else see this.”

**Notes for the Chapter:**

> So. This happened. Enjoy?

And so continued the cycle. They would fuck, knot, eat and sleep. Then one of them would awaken and initiate fucking all over again. During a normal cycle, it was usually Levi as he simply needed less sleep. But on this occasion, Erwin found himself being the sex pest. Sometimes it was merely lust that awoke him. Other times it was that his balls were actually painful and swollen. One time, even after penetration had occurred, Levi didn’t even fully wake up until the pain of the knot startled him; Erwin had felt particularly bad about that.

In between bouts of sex, Erwin made more feverfew tea and told Levi to drink it. His mate's flu symptoms seemed to wax and wane as the remedy would wear off. They both would nibble on some tasteless rations, and then Erwin spent some time rubbing his mate's aching joints.

The next time his body woke him to seek more sex, the alpha made sure to awaken Levi gently, showering him with kisses and combing his fingers through the dark hair, nibbling on their mating mark. When he wasn’t in rut, sometimes Erwin liked to wake his mate up with a blowjob. It wasn’t something alphas typically did, but Erwin knew Levi enjoyed it, and he himself liked the feel of the omega’s cock in his mouth. It was smoother than his, not requiring the excess skin at the base for inflating into a knot. And it would spit out a tiny load of clear cum when Levi finally came, which he had to admit tasted pretty good. Definitely better than his own. During rut however, his mind couldn’t have cared less about Levi’s external genitals. He had his own to focus on taking care of.

Erwin rolled Levi onto his stomach and grabbed his hips, angling them up so Levi was on his knees with his face pressed to the ground. Levi was more than strong enough to refuse to move if he didn’t want to get into position. But right now to his heat-addled mind, nothing sounded better than getting on all fours and be mounted from behind.

Rubbing his ass against his mate imploringly, Levi groaned, “Alpha, please,” knowing that his mate would be totally unable to refuse him. With a roar, Erwin plunged in, pounding into the slick passage. His cock was hot and heavy; everywhere it touched Levi inside produced sunbursts of pleasure.

Too soon, Levi felt his body clamp down again, effectively stilling the alpha on top of him, allowing him only to rock back and forward slightly once his knot had filled. There was a sudden rush of pain, and then Levi’s body tightened in orgasm, enjoining Erwin to release inside as well.

“My knees are going to be ruined,” Levi complained, knees already feeling scraped and sore on top of the aches he felt from the flu. And being thrown from his horse.

Big hands ran down his sides and back. “Sorry,”

“No you aren’t,”

The room stank of cum and sweat, of Levi’s submission and Erwin’s domination. The sack they had been lying on was almost stiff with drying semen, and Levi’s legs were stained from where Erwin had dripped out from him. He needed a bath. Ten baths. And as much as Levi was not enjoying being covered in their passions, Erwin was loving it. The territorial side of him revelled in seeing his mate sticky with his cum, knowing that he was stuffed full inside too.

The thought made Erwin rock his knot forward into his mate, driving the breath from him in lovely little pants. Where Erwin pressed his hand to Levi’s lower abdomen, he could feel the change from where organs had to shift to accommodate him, and it drove Erwin wild. The to and fro motion of his knot set up another chain reaction in his mate. Muscles fluttered around the head of his knot, milking another orgasm from him.

As he came, one thought kept going through Erwin’s mind. God he was thirsty. Erwin felt as though he’d produced gallons of semen in the last day, and was completely parched. Once he’d finished coming, he tried to lean over to where one of their water skins was sitting, but they were still knotted together, and the motion tugged on Levi causing the omega to hiss out in pain.

Glaring over his shoulder at him, Levi snarled, “What are you doing? That fucking hurts. Are you trying to pull it out?”

“No, I’m trying to reach something.”

“Can’t it wait?”

“It’s the water over there. I’m so thirsty,”

“There’s one here, let me see if I can get it. I could do with some too. My throat is killing me,” Levi leaned forward towards the other water skin in front of him, pulling on the knot joining them. In Erwin’s head, loud alarms went off, telling him that his mate was attempting to disengage from their mating lock. Instinctively, Erwin’s hands shot to Levi’s hips to still him, and he released a cloud of angry, dominating pheromones; the message was clear, signaling the misbehaving omega to cease his fruitless struggling and commanding him to be still. Collapsing into a little heap, Levi’s limbs gave way beneath him at the intensity of the smell.

Oops. 

“What the fuck Erwin?” Levi was now trapped beneath him, now totally unable to move until the pheromones dissipated. But he could still mouth off. "You dick!" 

Erwin blanched, “I’m sorry, I didn’t mean to,”

“I can’t fucking move!”

“I’m sorry. It was an accident. You tugged too hard.”

“I hope you die of dehydration,”

“I might.” The thirst was almost unbearable, “I’m surprised there aren’t just puffs of air coming out when I orgasm.”

“This is so undignified,” Levi’s voice was muffled where his face pressed into the stone floor.

Erwin felt really quite bad for his little mate. The fight had drained out of Levi under the primitive, controlling influence of the pheromones the alpha had inadvertently secreted. He tried to get them both comfortable, but the only way to really do that was to get Levi flat on his stomach. Erwin went to straighten out the omegas limp legs so that his ass was no longer perked up into the air.

“Ooooph,” unfortunately he moved Levi’s legs simultaneously, causing the omega to flop ungracefully onto his front, knocking the air out of him, “What are you doing now?”

“Trying to get you more comfortable.” Erwin turned Levi’s head so that it wasn’t face down, and then tried to hover over the prone figure under him so that Levi didn’t have to take his weight.

“I have an itch on my nose,” Levi wriggled his nose slightly.

“Here?”

“The other side. Keep going. Great. Thanks.”

While still trapped in his own body, Levi felt his pelvis start to throb again. “Brace yourself,” was his only warning before the two found themselves forced to endure yet another orgasm.

Erwin palmed at his balls afterwards. “There’s nothing left. I can’t go again.”

“Well we’re probably going to still be here for at least half an hour. So that’s- what? At least five more times? And then only four more days to go.”

The only bad thing about mating cycles was the fact that they got less and less fun as the two individuals involved got more and more tired and fed up. Erwin would have given almost anything for his knot to go down right about now.

Under him, Levi had started shaking slightly and was repeatedly swallowing and panting.

“Erwin, I don’t feel so good,” The unexpected rasp in Levi's voice caught Erwin off guard.

Levi’s back had broken out in sweat, and the pleasing red flush of heat over his upper back and chest had changed into a paler, sickly, patchy pattern. With a lurch, Levi vomited heavily onto the floor in front of him, but being still immobilised by Erwin’s scent, the omega was unable to move up and away from the puddle. The smaller man then made a horrible choking noise as he inhaled some of his stomach contents back into his lungs. Shock and fear registered in grey eyes as he tried to draw another breath and couldn't.

Panicking, Erwin hoisted Levi’s chest off the floor and hit him hard on the back to try and get him to cough it up. The rise in intra-abdominal pressure caused by Levi being sick set up another series of involuntary pelvic contractions.

“No, not now,” Erwin pleaded. But even as he spoke, he felt himself succumb to the tightness that enveloped him. As he came, Levi made an agonised sound and vomited again, this time all down his front, also covering Erwin’s arms where he held the omega.

When Erwin came to his senses, Levi was leaning forward still limp in his arms, weeping and coughing and wretching. The omega was making an odd high pitched noise when he took a breath in, as though his throat were too tight, and his breathing was wheezy, rapid and shallow. 

Something was wrong with his mate. Levi was getting sicker, and Erwin was helpless to do much else than hold Levi's face off the floor to prevent him drowning in his own vomit. 

If they were face to face then Erwin could have lifted Levi and carried him elsewhere. He could have wiped the puke away and made sure Levi could breathe. In doggy they were essentially trapped on their knees on the floor. The tugging brought on by trying to move would not help the situation. He couldn’t even see Levi’s face properly like this.

Genuinely frightened now for his mate’s safety, Erwin felt sweat begin to bead on his own forehead, “Fuck, we need to get help,”

“No,” Levi pleaded weakly, “no please don’t let anyone else see this.”

“We have to,” making the decision for both of them, Erwin bellowed towards the door to summon the two betas.

They came quickly, almost gagging at the smell that held absolutely no appeal for their phenotype. The shock on their faces would have mortified Erwin, if he weren’t so concerned for his mate. No one wanted to see their Commander and Captain knotted together and covered in puke and semen.

Holding Levi in such a way as to try and preserve any remaining dignity they had, Erwin turned on his most fearsome Commander-mode, “I need you to get water and towels. The Captain isn’t well. And grab that bag and brew some of the herb in it into tea.”

Levi hung his head, unable to look up. He was shaking and sobbing quietly.

“Levi, it’s alright.” He couldn’t even stroke Levi’s hair as his hands were covered in rapidly cooling vomit, “It’s all going to be fine. It’s just vomit. We’ll get cleaned up and I’ll leave and we’ll stop. Alright?”

“How can we fucking stop?” The small chest heaved, “We’ve barely started. You know I’ll just come and try to find you.”

“I’ll tell the other two not to let you.”

“It’s happening again,”

Aiming Levi back towards where he’d already vomited on the floor, Erwin held him firm through the wretching, with only bile now left to come up. The vomiting once again stimulated the mating reflex, and Erwin cursed himself as he yet again lost control. Panting and with his heart pounding from exertion, Erwin wiped one of his puke-covered hands on his own body to get it a bit cleaner, then brought up the hand to Levi’s face to wipe away some vomit that had managed to come up through his nose.

“Erwin, that’s fucking disgusting.”

“I don’t want you choking again. Can you move yet?” Now that the door was open and Erwin was frightened rather than trying to mate, he hoped the pungent scent from earlier would disappear and the biological imperative paralysing his mate could cease, allowing Levi to regain control of his body.

“No. Fuck, this is fucking awful. Where is a titan wanting to eat you when you most need it?” Levi was silent for a few moments, then groaned as his body began to betray him once more.

As the betas walked back in, they were greeted with the sight of their Commander in the throes of ecstasy, pummelling his hips against his much smaller mate’s backside, who had resumed projectile vomiting across the floor.

Half an hour later when they finally unknotted, Erwin tried his best to clean up his mate, knowing that he would hate anyone else doing it. The betas had sorted out the floor and made some more herbal tea. Levi was shaking and still relatively immobilised, teeth chattering and covered in goose pimples. Erwin was sure part of it was from the shock and misery of what was happening as well as the illness. Half the bag of feverfew was used up now, and it didn’t seem to be having as strong an effect as it had the day before. In fact, Levi seemed to be getting worse.

He convinced Levi to drink two cups this time, to try and replace the fluid he had lost, as well as see if the higher dose would reduce the fever. He’d had to assist him, as Levi seemed to be having difficulty holding the cup on his own.

Smoothing the wet flannel across Levi's face, Erwin tried to murmur reassurances to him. Then, wringing out the cloth and wetting it again, he dragged it across Levi's chest and neck, behind his ears and along his hairline. Most of the vomit had been cleaned off him.

"Blow," Erwin held the cloth to Levi's nose. 

"It burns." 

"Blow,"

Levi did as he was bid and Erwin managed to clear the remaining bile from his nasal passages.

Drying his mate with a towel and redressing him in boxers and Erwin's own shirt, the alpha sighed and pulled on his own pants readying himself to leave.

“Levi, I’m going to go now, alright? Wagner will stay with you.” Placing a kiss on their mating mark, Erwin stood to depart.

“I don’t want you to go to Mitras without me,”

Erwin frowned, turning back to stare at his mate, “I’m not going to Mitras, Levi. I’m going to the other side of the keep." With rising trepidation he asked, "Do you know where we are?”

Ignoring or not hearing the question, Levi reached out to him, “I’ll come with you.” The omega trembled as he tried to get onto all fours to follow his mate. 

Kneeling back down and forcing the omega back into a sitting position, Erwin shook his head firmly, “No, you need to stay here.”

But Levi seemed feverishly anxious, hands shooting out to grasp at Erwin, “I don’t trust them to be alone with you. Those fucking pigs and their fucking treacherous plans.”

Concern at Levi’s non-sensical remarks made his forehead pinch in consternation, and he took Levi’s hands from where they were gripping his shirt and held them in his own, “Levi, we are beyond the Walls. You aren’t well. Do you remember?”

“I haven’t even ironed your shirt,” Levi was getting upset and had begun looking around for a shirt that wasn’t there. His fingers tightened around Erwin’s hands.

They were getting nowhere with this. And if Erwin stayed, his rut would soon get the better of him, and he would be compelled to try to continue mating when Levi was clearly unfit to do so. 

Puffing out his chest and trying to look intimidating, Erwin put on his best ' _I'm in charge here_ ' demeanour. He hardened his eyes and barked, “You _will_ stay here, Levi."

The order came loud and clear, and the omega was unlikely to be able to disobey such a direct command from his alpha. Levi startled at the tone, looking lost and bewildered at his mate's behaviour. 

The Commander instructed Wagner to come to find him if things looked as if they were getting worse. Then, against every instinct he had, Erwin wrenched Levi’s fingers from where he was gripping Erwin’s hands and headed out the door without looking back.

Levi was calling his name and pleading for him to come back, sobbing heart-brokenly, his voice anguished and echoing down the corridor. If they were ever parted during a mating cycle, Erwin would hear the lustful call of his omega in heat and be compelled to return. But this was different. It was the cry of his mate in emotional agony. Every atom of Erwin’s being screamed at him to return to Levi’s side and it took considerable control not to turn tail and head back to hold his distressed mate. There was a physical ache in his chest at leaving his omega to suffer and Erwin rubbed a fist over his heart to try and ease it.

On the way across the building, Erwin looked out of a window. The others must be coming back soon. They had to be.

**Notes for the Chapter:**

> God I'm horrible to these two. I'm so sorry if you were hoping for nice happy times with this story, but nope.


	4. 4

**Summary for the Chapter:**

> “Levi?” Erwin took in the occupants of the room. His mate stood across from the two doctors, and they all looked as if they were squaring off. “What’s going on here?”
> 
> Levi pointed an accusatory finger towards the younger alpha doctor. “That bastard got me pregnant!”
> 
> “WHAT?!”

**Notes for the Chapter:**

> Bwa-ha-ha-ha!
> 
> Uh oh Levi, what have you been up to?

By the time the others returned a day later, Erwin was beside himself with worry. Since the start of the second night, Levi had become increasingly unwell, and had continued vomiting profusely. When one of the betas had come seeking advice, Erwin had advised them to give up convincing Levi to eat rations and just try to increase his intake of the remedy left them. But the medicine seemed to have stopped working by their accounts.

They’d had to abandon their mating cycle, and Erwin had been forced to retreat to the other side of the keep to try and reduce the urges of his rut. The only luck they’d had was that the titans seemed to have remained dormant in the snow.

At first, Levi’s cries for his mate had rendered Erwin unable to eat or sleep with the separation anxiety such a call produced. His mate genuinely seemed to believe that Erwin was in danger and needed his omega to be by his side. Levi called out for forgiveness for something that his fever-addled mind imagined he must have done wrong, begging inconsolably for absolution from Erwin.

_“I’m sorry Erwin, please come back, it won’t happen again,”_

_“Erwin! I’m so sorry, I didn’t mean it, please come back to me,”_

_“Don’t leave me, please I love you,”_

It sounded nothing like the strong man Erwin knew and loved. Ceaselessly the calls continued, until Levi’s voice started to sound hoarse from the shouting.

For a while Erwin prayed for the shouts to end, for Levi to tire himself out and sleep. But when they finally did stop and the keep took on an eerie silence, it felt even more troubling.

A few hours before the others returned, the betas had beseeched Erwin to return, so worried were they that something was terribly wrong. When he saw his mate, Erwin gasped in shock. Levi was delirious and hadn’t kept any liquids down in over twenty four hours. Combined with his fever and heat he was dehydrated and could no longer even sit up unaided. Erwin took his pulse, which was fast and weak. He was wandering in his mind, lashing out and agitated. Then he would quieten down for a while and be almost unresponsive, before coming to with a bang and reaching out for things that weren’t visible to anyone else. He had stopped recognising Erwin, and had ceased to interact with anyone at all not long after his mate’s return. His heat had apparently ended prematurely; it was very unusual, but Erwin assumed it was the result of the omega being so very unwell.

Soon the thundering of hooves on cobbles announced the arrival of the others, and Erwin sagged with relief. The returning soldiers came straight away, jubilant about the mission success. But once they caught sight of those left behind, they sprang into action to help.

“How much feverfew did you give him?” On his return, the doctor’s eyes goggled in disbelief at the empty herb bag.

Erwin looked into the empty kettle, “I think he’s just had the last of it,”

In the end they’d had to force him to drink it. The betas had been required to fetch Erwin once the Captain had become totally unmanageable, as despite being an ill omega in heat, he was still incredibly strong. Levi had fought them constantly once he had lost his faculties, and even in his weakened state it had taken all three of them at one point to hold him down and coax more tea down his throat. Erwin had tried a quick taste himself the day before. It was utterly foul.

“But that was enough for a whole battalion, not just one man,”

Erwin paled at the doctor’s words, “But you told me to use it,”

“I didn’t mean _all_ of it. Feverfew poisoning can cause severe gastrointestinal upset, muscle weakness and confusion.”

The Commander opened and closed his mouth like a fish, unable to speak.

_Poisoning. He’d poisoned his mate._

So that was why Levi had started vomiting in the middle of their coupling. Erwin had assumed it was the flu getting worse. 

Erwin was shocked out of his reverie by Hanji.

“So how are we getting you both home?” Hanji spoke up, trying to come up with some semblance of a plan. “Shorty isn’t getting on a horse alone. Nor with any alpha.”

Putting on his commander's hat, Erwin straightened up and glowered seriously at everyone, “Put him in the middle of the formation riding pillion to a beta and hopefully with the way the wind is blowing his scent will stay downwind of the other alphas.” He felt in shock at what he had done to his mate, although he hadn’t meant to harm him. It was hard to concentrate with the thoughts swimming round and round in his head. “Hanji, you take the Commander’s position and I’ll go behind.”

“A sound idea.” The doctor looked concerned and was staring at the sick man lying on the floor, “Prepare whoever is riding pillion with him that he’ll probably puke all over them. He’ll also need tied to them to keep him upright.”

“Levi will get better though?”

 _“_ We’ll know more once we get back. Certainly, if we stop forcing more herbal tea down his throat it will help. I think he’ll need some time in medical once we return and we’ll give him some fluids there. In very rare cases liver failure can result from feverfew poisoning, but I don’t see any signs of that currently.” He put a placatory hand on Erwin’s shoulder on seeing his shocked expression, “First let’s get you both back and then we can worry about that.”

On the seemingly never-ending ride home, Erwin had to resist turning around every few minutes to look towards where Levi was in the formation. It was a better use of his eyes to scan the environment for danger, but while his rut raged, his brain wasn’t programmed to allow him to function particularly well anywhere other than in the bedroom.

As they re-entered the Wall through the gates, the townspeople had stared and tongues had wagged on seeing Captain Levi looking so unwell on returning and having to ride pillion, strapped to the rider to prevent his falling off. The people always looked forward to catching a glimpse of Humanity’s Strongest; the notoriously anti-social Underground street urchin turned soldier. To see him looking weak and ill would be poor for morale among the common folk. Then Levi had vomited again and Erwin was certain he’d heard the word ‘ _pregnant’_ being murmured through the crowd.

Well, the rumours would soon be put to rest when Humanity’s Strongest attended him to Mitras in a few weeks time. Assuming Levi was fully recovered by then which the doctor had assured him he should be.

The intravenous fluids in the San did their wonders, and by the next day Levi had perked up and seemed less disorientated, but was still feeling the effects of the flu and his heat cycle. Erwin hadn’t been allowed to visit for more than a few minutes, and had been forbidden from touching Levi just in case his rut got the better of him. Luckily it seemed to have calmed right down and he promised to return as soon as he was able.

After a couple more days, Levi was discharged and allowed to recover in their own quarters. Erwin’s eyes had narrowed when Levi had stripped off for bed the first night he was back in their rooms, and Erwin caught a glimpse of the toll that the combined illness and heat had taken on his mate. As usual, Levi had lost a significant amount of weight during his unexpected heat. His face was slimmer, thighs leaner and his vertebrae protruded too much as he bent over to pull up his pyjama pants. There was the usual bruising on his ass and inner thighs, and he had complained of his entrance feeling tender.

More than happy to provide aftercare, Erwin had offered to soothe it with his tongue, but Levi had turned him down, frightened that it might induce a mini-heat or cause limb paralysis again. Alphas often performed oral sex to care for their omegas and soothe them after vigorous sex or to prepare them for it. On some omegas it would have an almost paralysing effect. It tended to unnerve Levi, causing him to feel odd and unable to move, which didn't bother him when sex was on the cards, but he didn't much fancy it after their recent fiasco. 

Happily Levi seemed to have developed a ferocious appetite and before long had returned to a healthier size. Such was Levi’s hunger that he’d been forced to get up in the night to snack. Buttered toast seemed to hold particular appeal and Erwin kept waking up to crumbs on the bed sheets. The mess didn’t particularly bother him, but the fact that it didn’t seem to bother Levi either disquieted Erwin somewhat.

One evening at dinner in their quarters, Levi had actually picked up his empty plate to lick it clean after cramming all the food on it into his face. And the next day he’d used his bread to wipe every drop of remaining soup from his bowl. His mate was normally a polite, if poor eater, and Erwin was quite frankly struck dumb to observe Levi devouring his food the way that he was. And he’d stopped making tea and started drinking plain water. Levi was a tea addict; it was his only real vice. Perhaps he had gone off it since being over-fed it during the mission.

After dinner one night when Erwin had planned to bring up the subject, Levi had given Erwin his best come hither eyes, taken his hand and led him to bed. Rarely if ever did Levi take a bold lead, and Erwin certainly wasn’t going to turn him down and risk his reluctance to do so again in future. Despite feeling aroused at the omega’s forwardness, Erwin struggled to actually convince his body to ready itself for sex. Levi looked great. Felt great. And sounded great. But his normally fiery scent seemed more like a low smoulder these days and it wasn’t having it’s normal effects on Erwin’s libido.

But once foreplay was well under way, Erwin soon forgot about it and his body responded to the feel of his mate wriggling beneath him. Naked on the bed and kissing Levi’s stomach, Erwin noticed with some surprise that his mate’s lower abs were slightly less defined than they had been previously. Not really wanting to mention it lest the remark deprive him of sex that night, Erwin made a mental note to not get distracted next time and talk to Levi about it all properly. It wasn’t that he wanted Levi to diet. Some bodily reserves would probably do his mate good for coping well with his next heat, especially seeing as the last one ended prematurely and had been triggered by Erwin, there was a reasonable chance that the one Levi had due in two weeks would occur with its usual periodicity.

But the next morning, the topic never quite came up. Levi sat bolt upright in bed, startling Erwin awake.

Looking over at the clock, Erwin could see reveille was about to sound. He rubbed his face and tried to get the sleep out of his eyes, “Levi, are you-“

But he never found out what Levi was. For the other man brought up his hand to his mouth and entirely failed to stop the projectile vomit that shot across the bedsheets.

“Levi!”

Even considering what he had witnessed at the keep, Erwin had never seen Levi vomit quite like that. It must have been everything he’d eaten yesterday. And to make matters worse, Levi continued to wretch until he went horribly pale and collapsed backwards in the bed in a dead faint.

Scrambling out of bed, Erwin pulled the cord in his office to summon an assistant. The young man on duty that morning was sent packing to find and bring a doctor ASAP.

While waiting, Erwin got a cool, wet cloth and tried to rouse his mate. Levi looked a wretched colour and was sweaty; despite that, his skin was a normal temperature. He came to with a groan and profound relief flooded over the alpha.

“The sheets-“ Levi moaned weakly as Erwin patted his face and neck with the wet rag.

“Don’t worry about the sheets, I’ll change them.”

Trying to contain the mess, Erwin rolled up the soiled cover and tossed it into a corner, missing the doctor by mere centimetres as he came through the door. Torn between wanting to stay and also wanting to give his mate some privacy with the medic, Erwin looked at Levi for a signal either way. But Levi ushered Erwin out with a wave of his hand.

“Go and wash, Erwin. Let the man examine me and come back once you’re dressed.”

Leaving his mate with the doctor, Erwin hopped in the shower to clean off the specks of vomit that had managed to splatter onto him, and under the warm spray he puzzled over what just happened.

What if this was Levi’s liver failing after all that feverfew? It had been six weeks now, but perhaps it took a while for livers to fail? Erwin felt rather helpless; he didn’t know a lot about medical matters and even less about drug side effects.

Dressing for the day, Erwin walked back into the bedroom with a glass of water for Levi, only to find the doctor readying to leave.

“I suspect it’s just a vomiting bug doing the rounds. Nothing to be overly concerned about,” the doctor sounded as though he was confident he knew what he was talking about, and Erwin nodded and began to remake the bed once the other alpha had left

“You are staying in bed today,” tucking the sheet around Levi, Erwin sat on the edge of the bed and watched Levi sip at the water he’d brought.

“But what about the trip to Mitras tomorrow?”

“You aren’t going if you’re going to be sick all the way there. That would be one seriously awful carriage ride for both of us.”

Conceding that on this occasion Erwin might be right, Levi looked at him as he took another sip, “So who are you going to bring?”

“Hanji maybe.”

“Ha. I don’t envy you being alone with Hanji for two weeks. Rather you than me. You won’t have as much fun without me either.”

“Of course not. No toilet jokes or terrible drinking games or anything. How will I cope?” Combing his hand through his mate’s dark hair, Erwin smiled at the memories of the good times they had together on their previous trips; their forays into the wilderness, the trouble Levi had gotten them into on different occasions, but also the things he did that amused and entertained Erwin enormously.

Levi continued to tick off things on his fingers that Erwin would miss, “And no one to unpack and fold all your shit, and make sure you actually look presentable before you leave the room. Not to mention the blowjobs.”

“Ah well, I will definitely miss all of that. Particularly the latter.”

“Maybe Hanji will indulge you. I’ll ask them to fill in for me.” Levi stifled a laugh as he spoke.

“No thank you, Levi.”

~~~

By the time they returned a little over two weeks later, Erwin expected Levi to be up and about, and certainly no longer sick. What he didn’t expect was to see his mate looking rather gaunt with deep shadows beneath his eyes. He stifled a gasp on seeing him, rattled at his mate’s appearance.

“Levi,” Erwin ran his hands along his mate’s torso. His ribs felt way too prominent, and his body too sinewy, “Are you still unwell?” He took a deep sniff of Levi’s hair, trying to determine if anything was obviously wrong; and on a subconscious level, his alpha brain sought to see if his omega had remained faithful or whether the scent of another alpha was present. There was an unusual sickly sweet smell, alongside the sour note of vomit.

“Yeah, I feel rotten all the time. Can’t even fucking sleep.”

“Go to medical. Right now. That’s an order.” His tone was sharp from fear.

Levi opened his mouth to protest, then went even paler (if it were possible) and threw up what little was in his stomach right onto Erwin’s boots. Waiting just long enough for Levi to finish vomiting, Erwin scooped him up and took his mate there himself.

Once he was satisfied that Levi was being adequately attended and had told the whole truth about how unwell he truly was, Erwin felt able to leave his mate in the medics’ capable hands.

“I’ll come by later and see how you are. I have a few meetings to attend now.” He made to kiss Levi, but the omega turned his head away.

“Vomit breath. You don’t want to kiss me,”

He settled for kissing the crown of dark hair and their bonding mark, and then set off to put on some new boots and ask someone to clean the ones now coated in puke.

~~~~

“What sort of fucking doctor are you?!” Levi's voice echoed loudly down the corridor. 

A terrified voice squeaked in return, “I’m sorry, I forgot that particular potential side effect,”

“Forgot?! That’s a pretty important fucking thing to forget!”

As Erwin approached the medical wing after his debriefings, he could hear his mate ranting and raving at some other poor soul in the San. In the thankfully otherwise empty ward, the big alpha doctor was cowering and looking terrified as Erwin’s little omega mate shouted and yelled abuse at him. The older beta doctor stood looking shocked, holding a set of papers and watching the rather one-sided verbal sparring match.

“Levi?” Erwin took in the occupants of the room. His mate stood across from the two doctors, and they all looked as if they were squaring off. “What’s going on here?”

Levi pointed an accusatory finger towards the younger alpha doctor, “That bastard got me pregnant!”

“WHAT?!” The bellow came out quite involuntarily at Levi’s words. His head turned to the alpha and Erwin felt his nostrils flare. His body language changed and he tried to make himself look as big and intimidating as possible. Horrible images appeared in Erwin’s mind.

Levi in this fucker’s arms.

Levi beneath this other alpha, taking his knot.

Levi crying out in ecstasy as this bigger alpha fucked him.

In a rare fit of anger, Erwin made to roll up his sleeves to punch the other alpha square in the face and rip his genitals clean off.

“You misunderstand Commander,” the older beta doctor stepped in between the two alphas in an attempt to stop the fight before it started, his beta scent calming things down a notch. “Feverfew reduces the effectiveness of Levi’s particular type of contraception. Your mate took it - in quite frankly enormous doses- during his last mating cycle _with you_ -“ heavy emphasis was placed on those words, “-and now he is with child as a result. There has been no secret affair between my subordinate and your mate.”

“Shit,” Erwin’s eyes swung from one person to the next. “You can’t be serious?”

“I’m fucking pregnant, Erwin.” Levi began to pace the room with his head in his hands. “Shit, shit, shit!”

“Are you sure?”

“Yes,” the older doctor spoke, holding up the paper with the test result on it for Erwin to read. “There’s no question of it.”

B-HCG: 1000

Result: Positive

Erwin stared at the piece of paper as though doing so might change the result.

“We will step out and give you both a moment to talk,” the beta doctor pushed his colleague unceremoniously out of the door and closed it behind them. Behind the door, Erwin could hear their raised voices; one angry, the other conciliatory.

“What are we going to do?” As close to being on the verge of tears as Erwin had ever seen him, Levi was wringing his hands frantically with worry and the scent of his distress filled the room. Erwin moved to comfort him but not before he too was confronted by his mate’s wrath.

“And _you_!” Levi rounded on him with fury in his wet eyes. “Did you seriously fucking think I’d slept with another alpha? With that big ugly brute?”

“Not really, no. I don’t doubt your fidelity. I never have.” It had merely been an instinctive reaction to Levi’s unclear statement.

“Hrrmph,” Levi crossed his arms and bowed his head; he had never looked smaller.

Sensing just how distressed his mate was, Erwin enfolded him into his arms and they stood holding each other in silence. He was sure his own scent was one of fear and anxiety, rather than the soothing confident presence Levi needed at that moment.

“Let’s sit down and talk about this,” he murmured into Levi’s dark hair. Guiding him to sit on one of the hospital beds, Erwin clasped their hands together and tilted Levi’s face up to his own.

“What’s there to talk about?”

“Tell me how you feel?”

“Fucking terrified." Levi's hands shook, and he pressed his face into Erwin, "This wasn’t supposed to happen. Do I have to stop training now? Can I still go out on missions? You’ve never gone on a single one as Commander without me. And then what about getting this thing out of me? How’s it going to fucking fit? You said yourself I’m too small. What if I die? Or it dies? Or we both die? Remember the last time? What if-?”

“Levi, listen to me.” Despite having all the same fears, Erwin felt one of the pair had to be the voice of reason. “Not all pregnancies reach term. Especially in omega males, you know that. Let’s take things one day at a time for now,” He tried to keep his voice strong and cheerful, despite feeling anything but on the inside.

His mate looked weary and upset; the changes Erwin had witnessed all now made sense. The change in scent in particular should have caught his attention. It made Erwin feel overly protective and want to cuddle his mate all day long. It made him want to bring Levi choice treats and shower him with affection, rather than chase him into bed and nibble and lick him all over as it normally did.

“What about if I took some of that weird fennel stuff that Hanji said works to abort pregnancies?” The words were spoken into Erwin’s chest where Levi’s face was pressed tightly.

Deep within him, an uneasy feeling built at the suggestion. Erwin stroked Levi's lower back soothingly, “We can ask. It works on women for sure. I don’t know if it will work for omega men.”

“Can we go back to our room now?” The pleading tone was so unlike his younger mate as to worry Erwin even more.

Holding Levi at arm's length to get a look at his face, Erwin asked, “Is there nothing they can give you for the sickness?”

The dark head remained bowed and shook from side to side, “They recommend ginger tea. But honestly I don’t think I could stomach even that at the moment.”

He nodded, “Fine. Let’s go to bed. You need to sleep and I’m pretty tired from the journey today. Perhaps you’ll sleep better if I’m here with you.”

“I’d like that. I’ve missed you,”

“I’ve missed you more.” They kissed chastely, Levi’s small hands coming up to cup Erwin’s face. Closing their eyes, they rested their faces against each other from forehead to nose.

“You stink of four-eyes. Did you and Hanji cuddle much?”

“Mmmmm. More than I would have wished. The bed we had was super small. I often woke up to find them plastered to my back.”

Smiling despite himself, Levi sighed, “That’s because you’re like a furnace.” Standing up and stretching, Levi made for the door. As he stretched his shirt rode up and showed off his lower stomach. Erwin peered at the visible skin, as if expecting him to already be showing. Naturally, that wouldn’t happen for a while. Nor would he quicken any time soon.

Back in their quarters, they both got ready for bed despite it being only late afternoon. They bathed, and then Levi had grabbed one of his contraceptive pills out of habit and was about to throw it in his mouth. Then he pulled an expression as he realised that there wasn’t much point anymore. He put it back in its container with a sneer.

They climbed into bed and lay stiffly beside each other in an awkward silence. Tentatively, Erwin rolled onto his side and reached a hand over, setting it on Levi’s chest. Then he slowly moved it down until it rested above Levi’s pubic bone. He put no weight through his hand, but let it almost hover as it lightly touched the skin.

“You aren’t going to crush it with your big, meaty hand,” Levi scoffed, and brought up his own hand to lay it on top of Erwin’s, forcing it to rest down on his abdomen. Then Levi laced his fingers atop Erwin’s thicker ones.

Erwin stared at where their hands lay.

There was a baby in there. His baby. Their baby.

He felt elated. Perhaps this little person would be their legacy. Their gift to humanity.

At the same time, fear crept into his thoughts. Very little frightened him truly. But the thought of Levi not surviving this, or being unable to return to active duty terrified Erwin more than he wanted to admit. The thought of being alone again was too much to bear, not after they’d both found each other and made some odd sort of happy life together under such impossible odds.

The presence of his mate back in their bed had soothed the omega. Levi had rapidly fallen asleep after becoming horizontal, long before Erwin ended his unhappy train of thought. Erwin scooted closer and hooked an arm beneath the pillow under Levi’s head. Still asleep, Levi turned so his back was pressed to Erwin’s stomach, their hands remaining entwined. Erwin buried his head in Levi’s hair and took a deep sniff. The scent of his mate had definitely changed, and even though it had been a long time since last experiencing it, the primitive part of his brain remembered it immediately. Warm wood, bay and cotton; soap and lemon and some strange new ineffable sweetness.

He smelled like home.

**Notes for the Chapter:**

> Well I hope that sorts out some questions some of you may have had.
> 
> The strange sweet smell from Levi is due to ketosis from starvation btw if you are interested.
> 
> So this story may end up being a massive angst-fest, or could be really super sweet. Please comment and let me know which you guys would prefer. Or you know, I could do alternate endings. But I'm not sure how satisfactory that feels. If no one says anything, we're taking the angst train downtown. Wooo wooo!!!


	5. 5

**Notes for the Chapter:**

> Flashback time!

_The Underground: Fourteen years earlier._

There had long been rumours of a boy in the Underground, whose skill at the ODM outranked even the best veterans in the Survey Corps. Although Erwin didn’t necessarily take all rumours at face value, he was eager to see if this mythical rogue was the real deal. And so, he found himself somewhere he never thought he would ever go- the sewers under Mitras.

A stinking and wretched place, Erwin wasn’t surprised that those who were trapped down here needed to resort to criminality to eke out an existence in their short lives. From his sources, this boy had apparently stolen the ODM gear and ID of an alpha MP member who was frequenting an illegal omega brothel which specialised in providing underage children to its patrons, leaving the soldier trapped in the Underground and in a lot of trouble once he managed to return to the Surface. The MP Commander had issued a harsh corporal punishment as a lesson to anyone else who thought they could indulge thusly. Erwin smirked, and couldn’t help but think that the other alpha deserved every last crack of the whip he got, although most of them were for losing his gear and bringing the MP into disrepute rather than his committing a blatant sex crime.

For many days, Erwin and several other scouts were encamped down in the squalid city keeping their eyes peeled for the boy with the stolen gear; his subordinates were suitably unimpressed at their mission, and visibly struggled with the stench and chill.

And then, just as Erwin was starting to give up hope of finding him, he saw it. A shadow in the air, moving silently and faster than any soldier Erwin had ever seen. Shooting his anchors into a stone bridge, the soaring figure did a graceful one-eighty in the air and dropped down onto the roof of a small business. Having watched it for the majority of the day, Erwin had seen small packages and money exchanging hands, and suspected that the bread the vendor purported to sell was only one of his many wares, and not his most profitable. In seconds, the boy had grabbed a basket of food and was away once again, before anyone could hope to spot or stop him. Even with this short glimpse of him, Erwin was sure that this boy represented a revolution in the way they fought and trained their men.

Never had he seen someone manoeuvre this way; it was like this boy had been born with the wings of freedom as part of his very being.

He grinned up at the youth flying skillfully through the air with the stolen ODM gear. This boy was his. Heart pounding, Erwin’s eyes gleamed as he planned his next steps- capture and direct recruitment. A bold move, and one that had never been done before, but prison or execution would be a wasteful end to such a weapon. Based on his fighting prowess, aggression and strength, the boy was likely a young alpha. He would grow into a fearsome man.

Erwin nodded to himself; decision made. This nuisance of a boy would be captured and tamed before he became a real danger as an adult. No one would hesitate to shoot down a dangerous alpha criminal roaming the streets, nor would they likely receive censure or criticism. It would be political madness not to remove this boy from the streets, for the public's own safety.

~~~~

In the end, it took nearly twenty soldiers to bring the boy to heel. Erwin had to give him credit- the MP were completely unable to keep up with him, and he tried to escape rather than fight or maim anyone. Once cornered, three scouts were disarmed by a knife he had hidden on his person, and six more were knocked back by kicks and blows. Even Mike and Erwin together with their blades had nearly lost their own fight with the boy's small stilleto knife if it hadn’t been for the hidden Garrison snipers darting the boy twice. But instead of dropping unconscious, the boy simply yanked out the darts and fled once again; his aim and movements becoming slowly clumsier and unsteady. Finally, after two more darts were emptied into him, the boy’s eyes rolled into the back of his head and before Erwin could catch him, he dropped off the edge of the building and fell three floors face down into a large puddle on the street below. Erwin dropped swiftly down and turned him onto his back, scooping out muck from the boy’s mouth and removing the hood covering his head.

 _Please don’t have snapped your neck_ , he silently begged. The boy hadn’t really done anything to deserve being chased and darted, let alone be killed. Even at the height of the chase, he had seemed purposefully to avoid injuring anyone, only wanting to disarm them and escape.

The limp figure in his arms was small, probably just over five foot tall. He was bony and thin, as if he had recently tried to have a growth spurt but lacked the nutritional reserves needed to fully support it. The boy looked about fourteen, though it was hard to tell with all the mud now caked on him. But it was his face that really caught Erwin’s attention. Despite the filth, there was something about him that caught the alpha off guard. He had never been attracted to other alphas, or young boys. His preference was for omega men and beta women in their early twenties, of a similar age to himself.

Digging his nose into the crook of the boy’s neck ostensibly to check for breathing, he was unable to detect any scent except the overpowering stench of the sewage now covering him. A warm puff of air against his cheek assured Erwin that the boy was indeed breathing, though in the darkness it was impossible to check him properly for any injuries. Erwin sighed and pulled the now empty darts out of the other side of the boy’s neck.

In a flash, Mike was standing beside him, kneeling down to get his own look, “Feisty little bugger, isn’t he?”

“Yes. To say the least.” Erwin stood and carried the unconscious figure towards the nearest stairwell, trusting that the other Squad Leader would take over debriefing and ending the mission officially.

Giving his own sniff of the boy, Mike grimaced at the stink of the sewage water soaking his hair and clothes, “Are you sending him to the cadet corps?”

“No.” He gripped the bundle in his arms tighter to himself. “He’s going to be fast-tracked straight to us. I don’t want to risk him deciding to join the MP if he were to get in the top ten.” Which he undoubtedly would- Erwin was sure of it.

Mike let out a slow exhale, “I hope you are prepared to take responsibility for him, Erwin. The commander won’t want to have to train the runt himself. And when he grows up to be even bigger and stronger, you may find he isn’t so grateful to you.”

Taking the well-meant advice for what it was, Erwin nodded sagely, “I’ve already agreed to be his mentor.”

He got a hum of disapproval in return, “Just make sure you don’t end up as his next victim.”

“Oh Erwin!” Hanji Zoe’s excited voice rang in his ear as they caught up with him. They clasped their hands together as they peered at the still bundle, then looked up imploringly at him, “He’s amazing! Can we keep him, oh can we please, Erwin?!”

“You’ll have to help me look after him,” Erwin joked as he continued to walk. “Clean up after his messes and keep him well groomed.”

Following him like an excited child Hanji nodded, “I promise! And I’ll take him for walks, and feed him and pet him and love him and squish him.” They wrapped their arms around themselves and squeezed tightly.

He laughed, “We’ll see how well he likes that.”

“I can’t wait until he wakes up.” Their eyes lit up behind their glasses. “Then we can get him geared up and he can teach me how to do that weird flip thing.”

Normally not a man to get excited about much anymore, Erwin found he couldn’t wait either.

~~~~~

Once back at HQ, Erwin had deposited the still unresponsive boy in the san and headed off to wash. In the halls, people noticeable shrank away and held their breaths. He stank of human waste and decay, and wasn’t entirely sure his clothes were in any way salvageable.

Finally clean and redressed, he dropped his stinking clothes in the laundry room before heading back for an update on their newest recruit. The boy looked small in the big bed, and very, very pale. It smelled like someone had been sick.

“He was awake briefly. It’s quite incredible that dose of tranquiliser didn’t kill him outright, though he’ll probably feel rough for a few more days,” a pleasant nurse told him. “He told us his name- Levi. Poor thing has been puking a lot and falling unconscious again, but it’s no bad thing- it’s given us a chance to give him a good clean and examine him without him fighting us.”

“He has incomplete root growth of his molars,” the beta doctor said, crouching beside the boy and pulling back his lips to get a look at his teeth and gums, then taking the opportunity to examine him top to toe while the boy-Levi- remained in his stuporous state.

“Meaning?” Erwin hadn’t a clue about dentition. His gaze was focussed on the in-drawing between the boy’s all too-visible ribs with each breath in he took, and the bandage wrapped around his chest and shoulder.

“He’s an adolescent. Probably 15 or 16 years old. And his age is further evidenced by the fact that it appears he has yet to have had his first heat.”

“His first what?” Erwin performed a double take; surely he had misheard. Without meaning to, he glanced down between the boy's legs.

“Heat.” The look Erwin got from the older doctor suggested that he was some kind of huge moron. “He’s an omega.”

Erwin wasn’t sure he’d ever been so shocked at a piece of news in his life. He had imagined someone with such raw physical strength and talent to be an alpha, albeit a small, pre-pubertal one who still had a lot of growing to do once he got some proper nourishment in him. But from what he could gather from this little chat, this boy who had given them a long, hard chase and fight was an omega who had likely almost completed his growth.

Eyes trailing up to the boy's face, Erwin inhaled instinctively, and now that the boy had been washed there _was_ a subtle hint of scent that served to calm him. It was a trait designed to reduce aggression from alphas against omega children, and Erwin felt a wave of protectiveness wash over him.

In a way, Erwin couldn’t help but feel profoundly relieved. The boy’s allure wasn’t so strange after all. The idea of two alphas together didn’t go down well in their society. But if this boy was an omega…

 _Stop it_ , he admonished himself. _This is still a child._

A child who was unlikely to yet be experiencing the urges of an adult. And he was _so_ very small. There was little chance of compatibility with such an enormous size difference. He shook his head-it didn’t matter; Erwin didn’t want a mate, nor the responsibilities that came with it. He had chosen titans- anything else was a distraction.

~~~~

It was the next morning before he next heard anything about the wild child he had caught. Flagon had come to his office to ask him to report to the prison cells; the staff were finding the boy impossible to deal with since he had fully awoken from being darted, and everyone had agreed this was now Erwin’s problem.

“He tried to bite me,” complained Flagon as he followed the other alpha as they walked down the steps into the prisoner's quarters. “He just tries to scrap with you if you get too close. Can he even talk? All he’s doing is growling like an animal.”

Entering the cell in the basement Levi had been kept in, Erwin caught a glimpse of something quick moving across the room and darting behind a big examination chair. Grey eyes glinted out from around the arm of the chair before disappearing again. Sounding distinctly like a feral alley cat, the boy hissed loudly at him; a warning to not come any closer. The room still smelled faintly of vomit. Closing the door quietly behind him and setting down the bag he had brought, Erwin heard a _click_ as they were locked in from the outside.

“Levi,” Erwin stood for a moment to see if the boy would answer. “Are you feeling civilised enough to come out and speak with me?”

“Fuck off,” the boy’s venomous voice snarled from his hiding spot. Erwin had to smirk at the unmistakable accent of the sewers. That was one question answered; this boy hadn’t been in the cadet corps and deserted- he would never have been recruited in the first place with his biology and background.

“I understand that you are frightened.” Erwin took a seat in the corner of the room, his palms face up and trying to make it clear he wasn’t intending to be a threat.

From his position in his hiding spot, the boy’s head peeked up over the chair and he growled at the alpha, all wild eyes and bared teeth. At first glance, he seemed as utterly feral as Flagon had described, but Erwin could smell the fear rolling off him and felt a pang of sympathy.

“You were chased by a large group of men and woke up somewhere strange. You are scared. I get it, but I promise that we don’t want to hurt you.”

“You stole me,” came an accusatory tone, the boy speaking directly to him for the first time. There was a wobble in his young voice.

“I caught you,” Erwin corrected him. “If the MP had caught you instead, you would be in an MP jail now.”

“For running away?”

“For failing to yield to authority when they tell you to. It took a lot of convincing on my part for the brass to be convinced to give you a second chance. Consider yourself lucky to be here; being well taken care of. Be grateful.”

Head popping up again, the boy hissed at him, “You _know_ what I am. That fucking doctor told me you know. How exactly would you have me _demonstrate my gratitude_?”

“By joining us,”

“Huh?” This apparently took Levi completely off guard. His face and shoulders relaxed momentarily as he absorbed Erwin’s words.

Genuinely confused, Erwin gave the boy a serious look, “What did you think I was going to ask of you?”

Swallowing audibly and tensing up again, Levi’s eyes glanced down briefly at Erwin’s crotch, then back up to his face before they began to shimmer slightly.

Erwin’s breath caught. He hadn’t considered that a child this young would even think of being so mistreated.

“All I did was steal some food,” Levi’s voice took on a frightened whine. “I was just hungry, and if you knew _anything_ about the Underground, you’d know that the man I stole it from deserves worse that just having his fucking bread stolen.”

“He deals hard drugs.”

Levi stilled for a moment, eyes still wet, “Yeah. Among other much worse things. How do you know that?”

“I watched him all day.”

“Why?”

Voice firm, Erwin decided to tell the truth, “I was waiting to catch sight of you. As I said, I want you to join us. Your use of the ODM gear is very original, and I think you have the potential to succeed in military life if you give it a chance. And if you are worried about being taken advantage of as an omega-” Erwin tried to keep his voice calm, “-I promise that I will do everything in my power to make sure that never happens to you here. We want you to join our family and feel safe among our ranks. If you serve us, we will serve you too.”

Ducking down again behind the chair, Levi growled, “You’re an alpha. How can I trust you? Alphas lie to get what they want.”

“I _am_ an alpha, but I am also not allowed to fraternise with subordinates. That’s a rule here in the military and I would be harshly disciplined.”

The angry eyes appeared again, “You stole my clothes,” was levelled at him with undisguised fury.

Ah, so that was why he was hiding. Hospital gowns weren’t designed for dignity.

“They were too dirty to salvage.” Reaching into the bag, Erwin pulled out a fresh uniform and boots, “I have some new clothes for you,”

It had taken a bit of searching, but he had managed to find a cadet uniform that would fit even this small boy.

On seeing what was being offered, Levi sneered at him, “I’m not wearing that,”

Tone light, Erwin tried not to laugh, “It’s either this or you can go around wearing just that gown. It’ll be a bit draughty though.”

Blushing furiously, Levi ducked down again behind the chair and grumbled, “You wanted to watch? I’m not getting dressed with _you_ in the room,”

“I’ll leave you for ten minutes. When I come back in, I expect you washed and dressed. There’s soap and a bowl of water for you, and a towel. I’ll be back in ten minutes to take you to my office, and if you are still in that gown then that’s what you’ll have to walk around the HQ in.”

He stood to leave.

“Where am I?” The bravado and aggression had faded, leaving the boy sounding very lost.

Pausing before he left, Erwin turned to look at the wary little face peering out over at him. He spoke gently; truly the boy didn’t deserve to be treated badly, “You are in the Survey Corps HQ near Wall Maria. Ten minutes.”

He approached the bars of the cell and Flagon let him out.

Closing the heavy barred door behind him, Erwin peered up at the clock, “He’ll settle. He just needs a firm hand. Flagon, would you mind telling my Squad to practice their usual drills today? I need to get his paperwork done this morning and assign him a bunk and gear.”

Nodding and clearly relieved to not be dealing with the little punk himself, Flagon saluted and made himself scarce. Erwin stepped out of sight of the cell to give the promised privacy. After ten minutes elapsed, Erwin let himself back in without ceremony to find the boy dressed but still scowling at him, keeping a wary distance.

Erwin appraised him up and down, taking his dressing as tacit consent that he was indeed giving the scouts a try, “Good. Now, walk behind me and we will get the bureaucracy sorted. Needless to say, if you try to escape, the consequences will be even less pleasant than before.”

Stepping in line behind him and glad to escape the confines of the sick room, Levi asked, “What the fuck is ‘the bureaucracy’?” He could barely pronounce the word.

“Paperwork.”

Out of the corner of his eyes he could see the boy was still wobbly on his feet and wasn’t quite walking in a straight line. Perhaps he wasn’t entirely ready to leave his bed. “Can you walk?” Unsure now whether to wait an extra day to do this, Erwin considered returning him to his room. “Do you still feel drugged?”

Levi looked at him defiantly, slurring his words slightly as he spoke, “I’m dizzy, but I want out of here. Even if that means staggering along behind your fat ass.”

“Alright then.” He would deal with Levi’s colourful use of language later when he wasn’t doped up. A little military hazing once the drugs had worn off would do him no harm. Erwin had never considered himself the type to consider using physical force against omegas, and although this one was at least his equal in strength and fighting ability, he still wanted to try other methods to break him in before resorting to usual military corporal punishment for insubordination.

As they approached the hall leading to the entrance to the cells sunlight from the courtyard shone in brightly through the door at the end of the corridor. Erwin stepped through and paused at the bottom of the four short steps when he heard the quiet footsteps behind him cease. He turned to look back at his charge.

One of Levi’s feet hovered over the top step before retreating back in. The boy backed up a bit into the dark hallway and squinted up at the sky distrustfully.

Erwin turned and beckoned him with a tilt of his head, “I haven’t given you permission to stop. In the military you have to-”

“I’ve never been outside,” came the whisper-soft voice, interrupting him. Levi looked awestruck but apprehensive of the view awaiting him. “Not up here. I never even lived near one of the sink holes.” He pointed up, “Is that the sky?”

Looking up himself as if to check, Erwin felt his features soften, “Yes.” It hadn’t occurred to him that everything would be quite _so_ new to the omega.

“It’s blue with white bits.” Levi observed.

“The white things are clouds.”

“Oh,” came the breathless response. “They’re nice. Fluffy. The air smells nice here.” Stepping slowly out, Levi turned his head to the ground and shielded his eyes with his forearms as he moved out from the shadows, bumping into Erwin as he walked forwards, “It’s too fucking bright. I can’t see where I’m going.”

“It’s not far. We’re just going over the courtyard to that main building.” Taking Levi by the elbow, he guided him across and into the other building. “My office is on the third floor.”

Once inside, Levi was able to see slightly more clearly, though he looked as if he had a headache from the way his face was screwed up. He followed the blonde obediently enough, up the stairs and round to the spacious office.

As Erwin pulled the curtains to dim the sunlight streaming into the bright room, Levi cautiously stood with his back against the wall. Taking in the room, Levi’s eyes fixed on the door leading to Erwin’s bedroom, “Do you sleep here?”

Sitting at his desk, Erwin took out a folder and thumbed through the files he wanted, “Yes, through there is my bedroom.”

Looking slightly worried now, Levi’s eyes darted back to the exit.

Dipping his pen into the ink, Erwin began to fill in the boy’s paperwork, “I haven’t brought you here to show you my bedroom, just to do this. Take a seat. Surname?”

Reluctantly, Levi sat on the chair on the other side of the desk facing Erwin, “It’s Levi. Just Levi.” When Erwin looked up disbelievingly, Levi just shrugged, “Honest.”

“Alright.” Erwin left it blank for now. “Ethnicity?”

Again Levi shrugged. Looking him up and down, Erwin scribbled down a brief description.

Although medical had probably taken a detailed account of notable marks while Levi was unconscious, Erwin enquired, “Tattoos? Birthmarks?”

“None.”

“Tell me the extent of your education.”

Snorting in amusement, Levi shook his head almost imperceptibly as he watched Erwin’s pen scratch ink into the paper, “I can cut throats and do a drug run without getting caught.”

“Who taught you how to use the ODM?”

“No one.” Levi’s deadpan expression gave nothing away. “I just put it on and gave it a go. It isn’t so hard.”

“Can you read and write?”

“No,” the boy looked down at his feet.

“Have you ever seen a doctor or dentist?”

“No.”

“Do you drink alcohol?”

“No.”

“What drugs do you take?”

“What the fuck?” Looking at him incredulously, Levi scoffed, “I don’t take drugs. Don’t assume shit just because you think you’re better than me.”

Not entirely sure Levi was telling the truth, Erwin stared hard at him, “I’m not asking to pry or judge. I need to know whether you are at risk of withdrawing from anything. We can help you if that might be a risk.”

All he got was a glare, “It's not,”

“Good. Where are your parents?”

“Dead.”

It was like drawing blood from a stone. Erwin sighed out through his nose, trying to remain patient, “Have you been looking after yourself then? For how long?” He couldn’t imagine being a lone omega child nearing puberty was particularly safe anywhere, let alone in the crime-infested Underground.

This time Levi shrugged, “Dunno.” He peered up through his bangs, “Why do you care?”

“I want to know about you so I can come up with a training plan for you. I’m not sending you to the cadet corps, instead you will train directly under my supervision.”

This seemed to satisfy him somewhat. “Mom died when I was about six, I guess? I don’t know who my father was.”

“Mother’s occupation?”

“Whore.”

Erwin raised an eyebrow at him, and Levi gave him a scathing look.

Unable to hold back any longer, Levi snarled, “What do you really want with me?”

Reiterating yet again, Erwin kept his manner calm, “I want you to become a scout.”

“I don’t believe you.” Those teeth bared themselves again, the boy’s face contorting savagely. “You think you can fool me, alpha? You think I don’t know exactly what you want?”

“Levi,” Erwin set his pen down and placed his hands on the table, unsure what had triggered this off again. “I want you to become a member of the Survey Corps. To help me free humanity. That’s all I want, truly.”

Shoulders flattening and still looking uncertain, the boy asked quietly, “Do I get paid?”

“Yes. You aren’t a volunteer. Every month you will receive a salary.”

Eyes glinting at that, Levi licked his lips, “Where do I buy food? Where do I sleep?”

“Food is provided, and you will sleep in the barracks assigned you.”

The boy perked up at that, “Hot food? A real bed? With a blanket?”

His chest clenching at the innocence in the boy’s face and questions, Erwin nodded, “Yes, a real bed with blankets and pillows, and hot meals four times a day. You will need it to train and grow strong.” He began to list off Levi’s expected duties on his fingers, “You will have equestrian studies, general literacy and arithmetic lessons, practice maintaining and using ODM, plus engagement in general training and drilling. It takes a lot of energy to do all that work, so you need to make sure that you are eating and sleeping right.”

“I’m not great at sleeping.” Levi admitted.

“Where had you been sleeping Underground? Did you have a home?”

“No.” The omega shrugged, “I would sleep a few minutes wherever I found somewhere that was safe, dry and not a drug den.” He fiddled with a button on his jacket. “There are gangs down there that try and kidnap omegas, and stick ‘em in brothels for sick fucks to come down from the Surface for a good time. You daren’t sleep too long or they’ll find you.”

Frowning at the idea of human trafficking, Erwin tapped his fingers rhythmically against the desk, “It sounds like life hasn’t been easy for you so far. I hope here you can find a home. Perhaps you might even enjoy life here.”

“It’s cleaner.” Levi looked around, then asked with surprising interest, “Do I get to do cleaning? Do you have cleaning things? And somewhere to wash clothes?”

“Yes,” Erwin was taken aback, having planned on using the threat of cleaning latrines or laundry duty as a way of getting Levi to behave. “It’s usually a punishment to be honest, but if you feel you would like to contribute in that way then by all means knock yourself out. The kitchen staff will show you were everything is.”

Nodding, Levi suddenly looked a bit less tense.

“In terms of rank, you will start off as a corporal, and with time and good behaviour you can expect to be promoted. Unless a titan eats you first.” He gave a dark grin, and was surprised when it was mirrored back. Amused that they might share a black sense of humour, Erwin continued, “You will be in a squad, and they will be like your family.”

“My family?” Levi’s voice was uncharacteristically soft as he repeated the words.

“Yes. You will train together and spend time together. Your squad mates will have your back in the field as you will have theirs. You are accountable for and to each other. One day, they may be the ones saving you from being eaten by a titan.”

This idea of comradeship seemed to win the boy over more than anything else Erwin had suggested thus far. Levi cocked his head inquisitively, “Do we have a leader?”

“I will be your squad leader.”

“And who is _your_ boss?”

“Commander Vogt and his second in command Keith Shadis.”

“Let me guess. Are they both alphas too?”

“Yes.”

“Fucking great.” Levi crossed his arms. “Shit. Are there _any_ others like me at all?”

“No,” Erwin admitted, finding it rather amusing to hear such vulgar language on the tongue of an omega child. Usually they were brought up to be quiet and demure; nothing like the feisty creature in front of him. “Omegas cannot enter cadet training, so we have none as soldiers or officers.”

The omega looked exasperated at this response, “But isn’t that going to be a bit of a problem? You know, when one day in the not-too-distant future every alpha in sight suddenly sees me as a potential fuck buddy when I go into heat?”

“The doctor thinks you are still a ways off having your first heat yet, and besides from medical and myself, no one else knows. Everyone else has assumed you are an alpha or beta, so you can just keep up the pretence for a while at least. We may have fudged the rules to get you in, but I don’t think anyone here who has seen you in action could complain about you not being cut out for the military.”

Face a mask, Levi looked down at his hands, “Pretending I’m something I’m not isn’t going to work forever,”

“No,” Erwin admitted, “and I am trying to think of a solution to that. In the meantime, just don’t tell anyone. If you think you might be going into heat, go straight to medical.”

The boy looked up, curious, “How will I know?”

“I- uh-“ Opening and closing his mouth like a fish, Erwin was at a loss. He’d never anticipated having to explain the birds and the bees to one of his own squad, particularly not to an omega. “Well, you might feel- um-“ he tried to think how best to word it. “You might-“

“Great,” Levi deadpanned. “Well, I’m glad we cleared _that_ up. I feel ready for anything now. Thank you, Squad Leader.”

“Heh,” his cool façade breaking for a moment, Erwin scratched the back of his neck and leaned back in his chair. “Obviously I’ve never had one, but when I go into rut I feel too hot for my clothes and just think about getting into bed with someone. I imagine a heat is somewhat similar.”

“You think I’ll want to get naked with someone? In their bed?” Levi looked at him disgustedly. “No fucking way. I’ll _never_ want to do _that_.”

“We’ll see,” Erwin held back a chuckle. Collecting the paper, he shuffled them into order, “Well, that’s the majority of the paperwork complete. I’ll need to organise your vaccines, get you fitted for your gear and show you around, including where you’ll be sleeping. Then you are free to explore a bit, if you’d like.”

“I can hardly see,” Levi pointed out. “I’m practically fucking blind up here.”

“You’ll get used to it.” Stapling the sheets together, Erwin stood and gestured for Levi to do the same. “You must try and swear less; it may be normal Underground, but up here it comes across as overly aggressive.”

Eyes flashing, Levi gave a grin, “I _am_ overly aggressive,” he reminded him in his high-pitched voice.

“Ha, yes I know.”

 _I shouldn’t laugh_ , Erwin admonished himself. _It may only embolden him to continue._

Ushering him out of the room and down to the general sleeping area, Erwin showed Levi to an unused bunk in one of the male dorms. Levi froze on entering, taking a sniff and backing right back out again.

“You want me sleeping in a room with a bunch of alphas?” Levi hissed. “Are you fucking insane? I’m never going to be able to sleep in here.” The omega looked as if he were on high alert, unsurprising considering he had spent his life trying to avoid being asleep and unguarded near alphas.

“You won’t smell attractive to them yet, trust me.” He got a glare for this too. “My hope is that your prodigal skill will see you shoot up a couple of ranks relatively quickly, and then I can secure you your own private room.”

“My own room?”

“Yes. Behave yourself, survive your first mission and impress people with your skill. Then it will be easier for me to advocate for your promotion up the hierarchy.” Erwin took a sniff and regarded Levi for a moment. "You are welcome to use my own personal bathroom to shower in. It might be best to avoid using the communal showers, and in here try and change clothes as quickly as possible." 

The omega rounded on him, “Why are you doing this for me?” Levi’s tone was sharp and accusatory once more. “What’s in it for you?”

Normally, Erwin would have laid a supportive hand on a subordinate’s shoulder as he pontificated one of his well-practiced motivational speeches, but he found himself reluctant to touch the jumpy omega. Instead he clasped his hands behind his back and went to look out a window that overlooked the surrounding countryside, “I need good soldiers to help us reclaim land from the titans. I want to know where they come from and what they are. What we are doing at the moment is achieving nothing outside the Walls and just getting good men and women killed needlessly. We need a revolution in the corps; both in the way we think and the way we engage with the enemy. I have the brains and I need people like you to be the muscle behind me, showing results by effortlessly, fearlessly killing titans.” He turned to Levi and gave a proud smile, “Together, we can represent hope for the future. The people need hope more than ever. If an omega from the Underground can achieve great things, then anyone can.”

Looking slighted at the remark, Levi huffed and crossed his arms, “You make it sound like I ought to be fucking useless.”

Erwin lowered his tone, “I don’t believe that, but that’s what the people are made to believe by a lifetime of brainwashing by the church and the government. Help me prove them wrong, Levi. Help me show them that not everyone from the Underground is a criminal or unable to be educated; help me show them that omegas are just as capable as anyone of serving and making a difference.”

“Hmmmm.” Turning his head slightly and peering up at the alpha, the omega still looked rather disbelieving. “You really believe that? You aren’t just saying it? You mean it?”

“I mean it,” he hoped the conviction shone out through his eyes, and was pleased to see Levi give the tiniest of shivers. Trust wasn’t going to be built between them in a day, but this felt like a good foundation to build upon.

“Alright, Blondie.” Their eyes locked. “I’ll join your stupid club.”


	6. 6

**Notes for the Chapter:**

> I've been having such fun writing this story! Some of the later chapters will be longer, but for now each one will probably be about 4000-5000 words. We will be spending a bit of time in the past, and I think I've found a way to satisfy both the angst-seekers and the happy-ending seekers too. Personally, I love a bit of angst mixed with happiness, so I hope there's a bit of something for everyone in this fic. It will get dark though, but I'll be sure to put in warnings when that happens.
> 
> Your comments are always so appreciated, and help me work out what scenes to come up with in future- I read and treasure them all!

In the face of the rigors of strenuous training, Levi proved to be more resilient and stoical than Erwin thought possible of omegas- not that he’d known many. Close friendships with people of the opposite sex were discouraged when he was a boy, and since joining the military the only ones he had met were mated to high-ranking members of the nobility and government. They played a minor role in society at large as far as Erwin was concerned, with none in seats of office of in positions of authority. At a couple of fundraisers and charitable events, he had considered making an advance on one or two of them who had eyed him appreciatively up and down, wondering if it might make him privy to some interesting information about their alphas. While omegas were out of season, it was very unlikely that a child would result, unlike beta women who seemed to be able to become pregnant merely by looking at them too long.

 _This_ omega though was so utterly unlike every other Erwin had met. And to top it off, Erwin liked him on a personal level. He was a studious pupil, turning up promptly to remedial reading and arithmetic sessions with the school master that the novice cadets would study under until they were seventeen. Levi wasn’t the first cadet who had come to them unable to read and write, nor would he be the last. The omega had also impressed Erwin by adapting reasonably well to general military life- he was house proud when it came to presenting his bed space and clothing chest neatly every morning at inspection, and never slept in or missed a single training session. Levi’s gear and uniform were meticulously cared for, and he had fashioned a men’s cravat as an addition to his ensemble which suited him ridiculously well.

Casting his mind back, Erwin remembered that even on Levi’s first official day joining in training once his eyes had adjusted to the strong spring sunlight, that he had astonished and amazed his new squad with his abilities in the air.

“You hold them like this-“ Mike demonstrated, grasping the handles so that the blades faced forwards, “-and press in like this to release them when they blunt. Then you can attach new ones as required.”

Trying the hold out for himself, Levi had frowned at the way they felt imbalanced in his hands. Planting the blade in the ground to steady it upright, he slipped his ring and little finger of his right hand through the metal handholds and picked it up again. Now he was essentially holding it backwards, and he gave a small 360 jump to see how the balance now felt between the two. It was greatly improved, allowing him to spin and maintain angular momentum.

Flagon gave him a disapproving glare. “No, you’re holding that one backwards. They aren’t designed to work like that.”

Returning his own glare, Levi scoffed, “Well, apparently _I’m_ not designed to hold them any way but this. And really, all that matters is that I cut the nape of the bastards’ necks, right?”

Flinching back as Levi launched into the air, Flagon turned his glare onto Erwin who merely shrugged, “Watch him and see if you still think he’s holding them wrong.”

“I hope he’s been properly dewormed and tested for diseases. Who knows what pestilences those Undergrounders carry,” Flagon groused. “If I start to come out in mysterious itchy rashes, you’re the first I’m sharing them with.”

“Levi has received excellent medical care since joining us, I assure you.” At least, he was pretty sure that having received the appropriate medication that Levi was now infestation free.

As he had predicted, it didn’t take long for Levi to win over hearts and minds on demonstrating the unnatural ease with which he manoeuvred in the air and his uncanny ability to zero in on the fake titans’ weak spots. At one point he even managed to prevent one especially cocky soldier from skewering himself on a broken blade embedded in a fake titan’s neck. Erwin could only hope it all translated well onto the battlefield.

“Squad Leader!” Behind Erwin, a beta man in a white coat was running towards him with serious consternation plain across his face. Stopping to catch his breath and adjust his glasses, Doctor Brandt panted, “Corporal Levi has broken ribs. I must insist he be grounded while they heal. You told me he fell from three floors up only two weeks ago, and yet you have him out training already?”

Erwin looked across at the supposedly-injured boy zig-zagging through the trees; if he _was_ in pain, he was hiding it remarkably well. Either Levi had a high pain tolerance, or he was afraid to show weakness around his squad mates. Although they didn’t yet know he was an omega, it was probably no bad thing to awe them while he could- it might mean that they kept their respect for him should the truth ever come out. Erwin wasn’t sure how a bunch of betas and alphas would feel if an omega were promoted to a rank higher than them, and would therefore be able to give them orders.

Keeping his expression calm, Erwin shook his head at the news, “He never told me they were broken. I assumed they were just bruised. I’ll call him down at the end of this exercise and check he’s safe to continue.”

Looking unsure, the doctor initially looked as if he was considering pulling rank on this decision, which was his prerogative. Instead, he shrugged and stood to also watch the aeronautics taking place in front of them.

Gesturing for the man to follow him so they were aloof from the rest of the group, Erwin murmured, “Have you and your colleagues calculated an estimate of when his first heat is likely to occur?” Hopefully it was unlikely to be any time soon. “And a contingency plan?”

The doctor cocked his head to one side, “My best guess would be around the one year mark, after some serious weight gain. He needs at least twenty pounds on him before he is likely to trigger his first heat. When it happens, we’ll put him in quarantine and sedate him for the duration. We have enough beta staff on our books that caring for him shouldn’t prove an issue.”

“Should he start contraceptives now?”

Brandt looked aghast at the suggestion, “No. Omegas need to have their first heat undisrupted by exogenous hormone supplements or it could affect their fertility for the rest of their lives. After his first heat, we can discuss contraceptive measures. The right ones can help stabilise a fertility rhythm so he will have a predictable four per year, rather than have us on our toes until he is out of adolescence trying to guess when each heat will hit.”

“Is it so unpredictable?”

The beta nodded, “In teenagers, yes. Same as girls with their menstruation. It should even out with maturity. Usually heats will occur every four months, give or take a few weeks either side.”

Erwin frowned. He would have to work out how to time expeditions to preclude the chance of Levi going into season beyond the Walls without arousing suspicion from Commander Vogt as to why the dates were so very important.

“The other option of course is to pick him out a mate and have him present during that first heat,” Brandt suggested, giving the unmated alpha a knowing look.

With a jolt, Erwin realised the man thought he himself was grooming the omega to be his own mate. Coughing and looking away, Erwin shook his head, “I wouldn’t impose that on him. It’s one thing to recruit him involuntarily, it’s entirely another to do what you are suggesting. It seems highly immoral.”

Brandt shrugged, continuing to watch the recruits swinging through the trees, some more gracefully than others. “As you wish.”

Realising he knew all too little about omegas, Erwin asked quietly, “Do you have any literature he can read? I think we are both woefully ignorant about the anatomy and reproductive health of omegas, and could do with some information.”

“I’ll see what I can find. It will probably be aimed at alphas with omega mates, rather than omegas themselves.”

Giving him a disapproving look, Erwin’s frown deepened, “What are you saying?”

“It will be heavily dumbed down.”

Able to take a joke, Erwin laughed and gave the man a playful punch on the arm, “Hey, we aren’t all Neanderthals.” Though it _was_ hard to deny that some alphas were indeed all brawn and no brain.

“If you say so,” the beta man teased.

~~~

Later that week after a medical training session, Erwin closed the door to his office heavily behind him, leaning on it and closing his eyes. The room around him was cold and when he opened his eyes he saw that he had left one of the windows open all day. The curtains fluttered as the cool air seeped in from outside. Moving to start up a fire, he was dismayed to see that the hearth was still full of ashes. He had been too lazy that morning to clear them out. Deciding to just change into nightwear and try and warm up in bed, he lit a candle and placed it on the bedside table.

Once in bed, Erwin stretched out his arms behind his head; they hurt slightly after spending the last few hours learning the new technique of cardiopulmonary resuscitation, something that might apparently come in useful on injured soldiers. Erwin had his doubts; if a man was already dead in the field miles away from the walls, how much good would pumping up and down on his chest and blowing air into his dead lungs possibly do him?

Despite these doubts, Erwin had found the concept of reviving a dead heart fascinating. Every advancement they made, no matter how small or seemingly insignificant each was, was in Erwin’s opinion one step closer to humanity’s emancipation.

~~~

Having recently been made Keith’s personal aide, Erwin was excused from having his own squad to train and was free to manage his own time. Fully aware that he was being groomed to one day step into the commander’s shoes after Keith’s time had ended, Erwin spent much of his time attending formal events, filling in mundane paperwork and observing the higher-ups at play. Physical training almost felt like downtime in comparison.

One particularly nice day, Erwin set aside the dull monotony of paperwork to exercise in the sunshine. He planned to do a short trail, have a swim and then practice with the 3DMG. The men were running the long lap of the trail through the forest beside the HQ- a gruelling fifteen mile obstacle course that had to be completed within two hours. Able to take a break from his own workout to stretch out a cramp that had started in his calf, Erwin watched as the fastest group approached the lake. At the front, much to his surprise, was the small figure of Levi, who was practically sprinting along the trail. The grown men behind him looked exhausted at trying to keep up with him. At least they could briefly cool off in the lake before finishing the final two miles.

As Levi followed the well-trodden path to the small ledge overhanging the deepest part of the lake, he suddenly eyed the water and came to a screeching halt, digging his heels abruptly into the dirt and stopping just shy of jumping into the water. Unfortunately, the men behind him hadn’t noticed the boy stopping, and ploughed into him, knocking him clean into the lake. At first Erwin had to laugh at the comical shock that crossed Levi’s face, but when Levi failed to reappear amidst the splashing of the bigger men now making good strides across the lake, a sense of dread began to percolate through him.

Cramp forgotten, Erwin ran down to the lakeside and plunged in. The water was murky from the men having swam through it, and at first he was sure he was never going to find the omega. His hand gripped a log, and then some pondweed, before finally resting on something that felt like a set of shoulders. With one almighty push off the muddy lake floor, he emerged, gasping for air and dragging the unmoving boy to the shore.

Setting him on his back, Erwin looked at the still, toneless body. Levi’s lips were a horrible blue colour, and his skin was grey like a corpse’s.

 _Breathing. Check for breathing!_ Brandt’s eager voice said in his head. He placed the side of his cheek against Levi’s face.

Nothing.

Allowing himself to go into auto-pilot and trust his recent training, he pinched the boy’s nose, took a deep breath and clamped his mouth over Levi’s, pushing a breath in and seeing the small chest lift out of the corner of his eyes. Repeating it four times, he checked to see if the omega moved.

Nothing.

Yelling at some of the men approaching the water and ordering them to stop and get more help, Erwin placed his hands on Levi’s sternum and proceeded to push down hard and repeatedly to get blood moving in and out of the boy’s heart, wincing when he felt rather than heard one of the semi-healed ribs crack beneath his hands.

After around thirty more seconds, Levi’s body suddenly tensed up and he opened his eyes, sucking in a high-pitched gasping breath through his mouth that sounded like his throat was still clogged with murky water. Gasping himself and relieved beyond belief, Erwin sat him up and thumped the boy hard on the back. After a few more spasmodic breaths, the slaps on his back caused Levi to puke up a stomach-full of mucky pond water all over his own legs. Reassuringly, his lips started to turn from their lifeless blue back to their normal pink with every panting breath he took.

Erwin lowered him back to the ground and kept one hand firmly on his shoulder, “Lay down,”

The boy obediently did as he was told for once, limp as a ragdoll and still looking more short of breath than he had done running at full pelt down the trail. Still gripping him by one shoulder and hip, Erwin rolled Levi onto his side in case he needed to vomit again. Allowing his own pounding heart to settle, Erwin sat beside him and watched his face.

After a few minutes of both panting furiously, Levi’s cycle of breathing began to settle, and he tilted his head to squint up at him, “You-“ Levi heaved in a breath, “-you saved my life.”

Shaking his head in disbelief at what had happened, Erwin asked, “You can’t swim?”

“When-when would I have learned, exactly?” It was taking everything Levi had to talk.

“Take a minute to catch your breath.”

Doing as he was bid, Levi closed his eyes and remained sagged against the muddy ground, all strength sapped from him.

“Don’t you have bodies of water Underground?” Erwin eventually asked.

Looking exhausted, Levi shook his head against the ground, “Trust me, you don’t make old bones if you start swimming around in rat-infested sewer water. Or drink it. Most people drink weak beer rather than trust the water down there, even kids. It’s safer.”

Erwin grimaced, remembering the murky water he had been served with dinner in one grimy pub Underground. He was sure if he’d tried to drink it he would have been immediately sick. The beer they had ordered instead was warm and weak, but tasted pretty good.

“No, fair enough.” Squatting beside the omega, Erwin furrowed his eyebrows, “Can you stand? We should get you to medical, I think I re-broke one of your ribs.”

Rolling over onto his front and pushing himself up on wobbly arms, Levi pulled his knees up under himself and he visibly struggled to get onto all fours. It was five miles back to HQ, and looking at the way he was moving now, there was no way he was possibly going to make that distance. Despite running hard and being warm when he entered the water, the small omega was now shivering with cold from being wet and lying prone, which would only tire him further.

Erwin moved to help him up, and Levi shrank back. “I can do it,”

Letting the omega have a couple more tries to get to his feet, Erwin waited patiently for the boy to collapse again before putting a comforting hand on his shoulder, “Now isn’t the time to test your mettle. I know how tough you are, but you aren’t fit to walk. Let me help you back.”

~~~

It had been two weeks since Levi’s incident in the lake. Brandt had been thrilled at Erwin’s success with the CPR technique, and was excitedly writing up a report to send to the Interior Medical Council. The boy had made excellent progress, but this time had truly needed some time off from training to recuperate, much to Levi’s annoyance.

In the meantime, Erwin had found himself inordinately busy planning for future expeditions with Vogt and Keith. He had ideas for ways to reduce their men’s mortality in the field, but the idea wasn’t yet fully fleshed out. It had resulted in many late nights drawing formation diagrams, and much fuel for his fire when he would get exasperated at not being able to draw exactly the idea he had in his mind, scrunching up the papers and tossing them into the grate.

One night he came back to his rooms with an armful of paper and a new well of ink, determined that tonight would be the night he would finally get it right. Except, when he entered his quarters, he noticed a few small differences. Recently, he had noticed that in the mornings when he awoke, things weren’t exactly where he thought he had put them the night before. Initially, he wondered if he was indulging too much in the brandy he had been given on his last birthday, but last night he hadn’t had anything to drink. Yet, the room still looked different. The armchair was in a slightly different position, and it looked as if the floor had been swept. He cup stains on his desk were also gone.

Someone had definitely been here. Trying to think what they could possibly be searching for that required them to clean up after themselves along the way, Erwin felt a creeping sense of unease. Setting down his stationery, he planted his hands on his desk and leaned down heavily, planning how to catch whoever it was if they came again tonight. Maybe they were trying to steal his ideas? Or rifle through his personal papers. Whatever they wanted, Erwin was determined to keep his secrets to himself.

That night, he readied himself for bed as usual, and waited in silence for his uninvited guest to make their appearance. Sure enough, after another hour, he heard the _snick_ of a lock being picked and a small _creak_ from an old floorboard as someone stepped almost silently across the room. He gave it a few more minutes to let whoever it was do whatever they were there to do, intending to catch them in the act.

With a _bang_ he flung open the door, stalking into the office with a grim expression, waiting to see what was attempting to be stolen. Instead however, he was greeted by a surprised yelp and the figure of Levi leaping clean off the armchair beside the now-cold fire where he appeared to have made himself quite at home. The blanket covering him dropped to the floor, and a cushion was flung at Erwin like a projectile.

“Ooph!” Erwin caught it with his face. “Levi?”

“Erwin?” Freezing in his fighting stance, Levi swallowed hard, “I-uh-I didn’t think you were awake.”

“No? So you thought you’d come and hang out alone in my office while I slept?”

Shrugging, Levi picked up the blanket that was now pooled on the floor and settled himself back into the chair, resting his head against the wing. “I’m tired, and this is the only place I can sleep.” Looking rather like a cat, he snuggled himself into what looked like an awfully uncomfortable position before once again closing his eyes.

Erwin just stared at him, not really knowing what to say. He bent down to pick up the cushion at his feet, “Have you been sleeping here? And tidying my room?”

“Mmmhmmm.” Levi cracked open one eye lazily. “I can’t sleep in that other room. Too many alphas trying to out-stink each other. And this place is a mess. There's no way I could sleep with all those stains on your desk.”

“ _I’m_ an alpha,” he pointed out.

“Yeah, but you’re alright. And you smell nice.”

Feeling a blush rising at Levi’s innocently-made remark, Erwin was glad for the darkness of the room. “If I order you back to your dorm, what will you do?”

Still not deigning to open his eyes, Levi shrugged, “Ignore you. I tried sleeping in the stables for a week, but it’s getting too cold to do that.”

Marching over to lock the door to ensure no one walked in to find a subordinate in his quarters this late at night, Erwin noticed that it hadn’t been picked. “How did you get in?”

Eyes remaining shut, the boy pointed, “The window.”

“The window?” They were three floors up.

“I went across the roof.”

Knowing how nimble-footed the boy was first hand, and also how stubborn the kid was once engaged in an argument, Erwin caved, too tired to chastise him and really just very glad that he wasn't being spied on. “Get up,”

An unhappy look settled across Levi’s face, “Can’t I just-“

Approaching him and putting his hands on the chair back, Erwin spoke in a conciliatory tone, “I just want to move the chair.” It was a big piece of furniture, and wouldn’t slide across the floor without scratching the wood. “Help me lift it next door.”

Raising a fine eyebrow, Levi asked, “Next door? As in, your bedroom?”

“Yes. There’s a fire lit in there. I’ll put this beside the fire and you can sleep there if you want.”

The unhappy look vanished, to be replaced by something altogether more pleased-looking. It took a couple of goes to fit the big armchair through the relatively narrow door, but once it was in place in front of the roaring fire, Levi took up his odd sleeping position once more and pulled the blanket around himself.

Handing him his cushion back, Erwin noticed that Levi was still wearing his uniform-minus the belts. “Do you want to change?” Erwin offered, unsure if he had anything small enough.

“No thanks. I sleep fully dressed. I like being sure I’m ready for anything.”

 _He really is afraid to sleep_ , Erwin mused as he climbed into his own bed. Turning onto his side, he cast one last look at where Levi was snuggled happily in his armchair on the thick rug, the fire casting a warm glow across his fine features. The scene was reminiscent of his father’s chair by the fireside in his childhood home, and in an odd moment of déjà vu, Erwin felt as if perhaps Levi had always belonged here by his hearth.

“Goodnight, Levi,” he said softly.

A pause. “Goodnight, Erwin.”

~~~~

The next morning, he awoke as Levi was making his stealthy get-away. His blanket was neatly folded over the back of the chair and he had thoughtfully made up the fire again.

“Levi,” Erwin called after the retreating form.

The boy paused half-way through the door, probably expecting to be told not to come back.

“Tonight, don’t wait until dark before coming. I’ll be here from seven. We can spend some time doing some extra reading and writing practice. I want to show you how we construct reports and summarise figures from the field, or we can discuss formation planning.”

Looking as though he rather hoped Erwin had forgotten about his illiteracy, Levi shuffled his feet and pulled a face.

Erwin propped himself up on one elbow as he addressed the boy, chest bare and feeling less self-conscious about it around the omega than he had thought he would have, “I know it seems a daunting task, but you are clever and more than equal to the challenge. Learning to read and write will set you free, more than ODM gear and being able to fight ever could. It will be a kick in the teeth to those who wish Undergrounders and omegas to remain illiterate and trapped in a cycle of control and poverty. Besides, I hear you are doing very well indeed.”

“The others think I’m stupid.” Levi folded his arms across himself. “I’m the only one who’s having to learn it all from scratch, and I’m slow and shit at it. If they knew I was an omega, they wouldn’t even let me into their dumb class.”

“You undersell yourself, but you aren’t getting out of this. You learn best by doing- I’ve seen that for myself. Your progress might seem slow at first, but I’m sure it will pick up momentum soon. It’s not as if I expected you to be able to speed-read by the end of the first month. Tell you what, I’ll use some of my tea ration, and if you’re well behaved, I’ll even teach you how to write some swear words.”

 _That_ made the corners of Levi’s mouth quirk up. “Proper swear words?”

“Proper swear words,” he promised, nodding sagely, putting a hand over his heart.

Levi gave him the first proper salute Erwin had ever seen him make, “Alright, you got a deal. See you at seven.” Then he noiselessly stepped out the door and closed it behind him.

“Go out the main door!” Erwin yelled after him after failing to hear his office door opening. “Stop using the windows!”


	7. 7

**Summary for the Chapter:**

> So, we are still in the past and will remain there for quite some time! As I said before, this fic mirrors my main canon one, so there will be some plot overlap.

_It was nice having a roommate_ , Erwin mused to himself one morning as he shaved in his freshly cleaned bathroom. _Levi must have been busy while I was out yesterday_.

The room smelled of lemon and vinegar, and the white porcelain and tiles gleamed brightly in the sun coming through the translucent window. A patch of mould that had been forming slowly on the ceiling had been taken care of, and it looked as if Levi had even brushed the grouting with a fine brush.

Towel around his waist and one over his shoulders, Erwin lathered up shaving foam to perform his least favourite part of daily grooming. Unexpectedly, Levi came to stand beside him, towel around his shoulders like himself, an imitation in miniature of the older soldier.

“I want to learn how to shave,” came the childish voice, their eyes meeting in their reflections in the mirror. In that moment, Erwin remembered with fondness how shocked the boy had been on seeing his own reflection the first time he had caught sight of himself in the mirror. Levi had scrutinised himself in long silence, having never really seen his own face before. It was a nice face; Erwin’s favourite in fact, though Levi hadn’t agreed at first.

“Ha,” Erwin chuckled as he tipped his head back to reach the razor under his jaw line. “You don’t _have_ anything to shave.” He moved his jaw around to see if he had missed any spots, then stretched his upper lip down to rid himself of his faint moustache.

Looking at him glumly, Levi crossed his arms on the edge of the sink and rested his pointed chin on them, continuing to look up at Erwin. “When will I?”

“You might not,” he looked down at the boy. “Some beta men and omegas don’t. Count yourself lucky. It’s tedious waste of time to have to do this every day.”

The omega shrugged, annoyed at Erwin’s lack of enthusiasm for the task, “Just let it grow like Mike does.”

“I prefer looking clean cut.” Washing the razor in the sink, Erwin used the towel to wipe away the remainder of the foam from his face. “That reminds me, I have some information about sexual health and growing up that you might be interested in.”

“Sounds exciting,” Levi did not sound excited.

“I’ll read it with you,” Erwin offered, understanding that the complicated literature would be lost on the boy. “I know very little about omegas myself, and could do with an education. It has diagrams as well.”

“Alright,” Levi perked up. “You better not get embarrassed though like you did when I asked you about heats or I’ll tease you forever.”

“Heh,” Erwin threw the hand towel back onto its rack. “I’ll try and be more grown up about it all.”

“Tcch,” Levi tsked at him, neatening out the towel. “Hang your shit up properly.” Then he sauntered back out of the room.

The alpha chuckled. It had been several months since his roommate had moved himself in, and Erwin had grown fond of his presence in his life. The boy had become like his shadow and as time passed, people began to associate one with the other. Whenever Erwin passed anyone during the day as he went to the dining hall, training or meetings, they always informed him where Levi was if the boy wasn’t directly at his side. He knew that the same thing happened to Levi regarding himself, as the boy had observed one day that people seemed to believe one always needed to know where the other was.

It had been years since Erwin had to share a room, but this felt like a voluntary arrangement, and it didn’t irk him the way he thought it would. Levi slotted so seamlessly into his life. Like a cat, he would slip fluidly onto his chair beside the fire once darkness had fallen, stretching and yawning quietly before curling up for the night. In the mornings, Erwin would awaken to find his fires were lit for him and his boots would be neatly polished and ready by the door.

Cleaning the remnants of his facial hair out of the sink and finishing his ablutions, Erwin sauntered out into his bedroom nude to find some clothes to wear. He no longer felt self-conscious in front of the teenager, now lounging on the armchair, who was rapidly on his way to assuming best-friend status. The boy barely looked up from his book of childrens’ stories, unbothered about the sight of his naked roommate. Although Levi was much less frequently in a similar state of undress around him, it wasn’t particularly for propriety’s sake. Rather, Levi only showered a few times a week in the evenings before changing into a new uniform to sleep in, at a time when Erwin was often still burning the midnight oil in his office. He didn’t yet produce the musky sweat of men that meant a shower every day was mandatory rather than optional; neither had he experienced the mating swoon, and didn’t yet seem to see naked bodies in any particular sexual light.

It was a curious friendship in some ways; more like being a big brother or a mentor. It was sometimes too easy to forget that Levi was actually an omega- but as the months went by and the boy started in small ways to come a man, Erwin frequently found himself wondering how their friendship would change after Levi’s majority. Indeed, would he even still want to be this close to an alpha? It would be sad to have to live alone again and to wake up to a cold, lonely room every morning. Although he wasn’t sexually attracted to the boy, Levi’s face had a delightful charm that made it hard for Erwin to look away. His fine eyes held particular appeal, and his pointed chin and tiny nose became him. It made Erwin wonder what he might look like when he was nearer Erwin’s current age. Whoever was lucky enough to capture Levi’s heart would have themselves a fine mate, Erwin was sure of it. He just hoped that their sharing a room didn’t reduce Levi’s value in the mating market if he ever decided not to remain a bachelor. And what value he would have.

Omega males were becoming a rare commodity, partly due to their high childhood mortality rates- they often received poorer nutrition than their non-omega siblings which made them susceptible to illness. Some were killed at birth and those who weren’t were at higher risk of abuse and neglect compared to their non-omegan siblings, and they often recieved a poorer education. And yet ironically as adults, they were highly sought after, particularly strong and well-educated ones like Levi would one day become. Alphas were known to severely injure or even kill each other over mating rights during their ruts, and rich alphas tended to have more than one omega, narrowing the availability further. As a result of the unique bonding and biological mating process between alphas and their omegas, omegas were much more faithful to their partners than beta women, and a man could be more certain that the offspring he was raising were in fact his own. In general, only the highest ranking alphas could hope to find themselves with an omega partner. Squad Leaders in the Survey Corps had remarkably little hope for such a coupling. Forbidden from entering military life lest their heats screw up the minds of the men around them, omegas had been off Erwin’s menu for all of his adult life. He should have worked out what to do with this one pronto, but despite always having plans for everything else in life, instead Erwin had found himself procrastinating and just hoping things would somehow work themselves out.

Although Erwin found the idea of killing or neglecting any child distasteful, he felt as though part of him could understand the primitive need to produce strong alpha children in his own image. A man who produced alpha or even beta males was seen as virile and potent, unlike men who only produced female or omega offspring. Omega children in particular were often seen as a slur on a family’s bloodline, useless children that parasitically drained a family of resources. The fact that a strong, intelligent and handsome alpha such as himself was determined to remain a bachelor had some in the capital despairing. Indeed, society believed it was Erwin’s prerogative as a strong man to produce other strong men to lead humanity into the future, although he planned to do it through training other people’s children, rather than having to go through the rigmarole of making and raising his own. It was ego-stroking to have attention- he knew he was attractive, clever and had high value in the mating market, but he was single-minded when it came to his goals, and a family would hold him back.

This particular omega, however, was worth his salt. Once Levi became more literate, he seemed to relish helping Erwin with his paperwork. Having a partner in crime to help Erwin with the mundane report summaries he had to do also made the job easier to bear, not only in terms of reducing the burden of work, but the comfortable and companionable silence soothed him and made Erwin feel like he was missing out on having a social life less than he truly was. Everyone else Erwin’s age spent every evening flirting, drinking and gambling in the mess, and to be spending his twenties at a desk every night was terribly lonesome, and it frequently made him wonder if he was frittering his (likely short) life away. But now that he had his introverted companion (who quite frankly despised spending time in the rowdy mess filled with shouting, drunken men), their time together felt like they were doing it on purpose as an opportunity for bonding.

They had been on several mission beyond the Walls since Levi joined, and the boy was well on his way to becoming a veritable celebrity. Word of his matchless titan-kill count had already reached the Interior, and the common people would crane their necks out of their homes to get a look at him if he frequented their towns on his days off. Once Erwin was commander, it would be useful to have such a subordinate as a staunch ally- commanders were often hated for sending the sons and daughters of the people to violent deaths, and the masses needed a hero amongst those in the corps to look up to as a hero. He was determined to groom Levi to be his right hand man, and these evenings together were proving a good foundation for that plan. And he liked the kid- he wasn’t demanding, or troublesome. He was funny and caring in his own way. He gave his time and his effort, and performed numerous little acts of service which were beyond the call of duty, which meant Erwin had extra time to think about the bigger picture, rather than worry about when he next needed to clean his bathroom or change his bedsheets.

In return, Erwin spent his money on the boy- he liked tea, soap and lemons. He loved watching Levi’s eyes light up whenever he was handed his little gifts, and he inevitably shared them with the alpha. Some nights they spent time together playing cards- Levi taught Erwin how to cheat without getting caught- and some days they rode out together into the vast countryside surrounding the HQ to improve the boy’s horsemanship or to shoot, coming home with a sack of game for the kitchens.

One morning, after a late night summarising some particularly poorly written officer’s reports, Erwin awoke at his desk, head cradling his arms and drool pooling on the parchment under him. Sitting up straight and yawning widely, he stopped mid-stretch on seeing the teen opposite him mirroring his sleeping position on the other side of the table, pen still balanced in his hand and their half-empty cups of tea sitting cold between them. On hearing Erwin, Levi bolted upright and stared dazedly at him, still half-asleep. Across his face were traces of wrinkles from where he had lain over the seam of his jacket, and Erwin gave him a soft smile.

“Morning,”

Levi groaned, “Uhhhhh,” and set his head back down in his arms.

Erwin stood and tried to stretch out the small of his back. Walking round the table, he set a hand on Levi’s shoulder, “If you are still tired, go and have a proper sleep.” It was the weekend, and there was nowhere either of them had to be that morning. “Who fell asleep first?”

“Dunno,” came Levi’s muffled voice. He lifted his sleep-mussed head, “We still going to the lake today?”

Erwin looked out at the brilliant sunshine, “Of course. I’d almost forgotten. Perhaps we could nap there instead.”

“Mmmmmm,” came an affirmative sound, before Levi stood to go and ready himself. “I’ll steal some food from the kitchens to bring if you get the horses ready.”

“Aye aye, Captain,” Erwin teased, using the honorary title that the men had started to refer to the boy by.

Said boy rolled his eyes and shot the blonde his middle finger on his way out the door.

A few hours riding found them at the remote lake, the soundscape of the chittering birds and gently lapping water around them an all-encompassing song of life. Crunching through the dried sticks of the underbrush leading towards the shore, Erwin pushed back a familiar knot of low, twisted tree branches until he found their favourite spot. The grass had already been smoothed down, perhaps by a recently slumbering deer who also favoured this quiet part of the lakeside.

As Erwin entered the water, Levi stood preparing a hand-line to cast. The boy had gotten into fishing after meeting a local angler who had told him about the apparent joys of reeling in the elusive and slippery prey, and Levi had managed to find an old fishing hook in the storehouse that he had claimed for himself. Dunking down in the water and gasping at the coldness, Erwin stood up and pushed his wet hair out of his eyes. Levi had disappeared from the shore, and a while later he returned with a handful of live worms that he had managed to bring to the surface through means unknown.

Erwin remembered the first few times Levi had tried this, cussing out his lack of skill and success and blaming the alpha blundering around in the water for scaring away all the fish. Slowly though, he had improved. As Levi’s eyes had tracked the dark and tempting shadows gliding gracefully beneath the waters, finally the weight of one had tugged at the gossamer-thin line he had wrapped around his hand. A sparkling silver, iridescent blue-grey thing was lifted out of the water, and Levi’s proud eyes had matched it in liveliness. The fish hadn’t been the only thing that was hooked that day.

“I never got into fishing,” Erwin remarked, scooping up some water and throwing it on his face. “You and father would have gotten along well; he adored it. Where he grew up downstream from local heavy industry, the river ran black with coal dust, so there was nothing to fish for. His childhood experience is one of the reasons he wanted me to grow up outside of any of the big cities.”

Looking at the crystal clear water, Levi hummed, “I don’t think I’d like to live in a city ever again either.”

“Maybe try doing your fishing _after_ I’m done swimming around and scaring them all off.” Erwin chucked a handful of water at the boy, “Come in and play with me.”

Soon, the two youths were messing around in the now-disturbed lake, their clothes in neat piles on the small sand-bank. Cupping Levi’s foot in both hands, Erwin hauled the omega’s weight up, and Levi gracefully flipped backwards up into the air, arching his back and splashing headfirst into the water. Erwin had gasped in shock as the boy then swam between his legs under the water, before coming up behind him and leaping onto his back. Laughing, the blonde tossed himself backwards and initiated a play fight, emerging to receive a face-full of water the boy spat at him. Levi had taken to the water well since starting to learn after his incident during training; nervously at first, but it hadn’t taken long for the teen to become a proficient swimmer and become unafraid of diving down into its depths.

Blinking the fresh water out of his eyes, Erwin took a deep breath and disappeared down himself, pushing himself off the muddy bottom and launching himself hard at the other. He managed to haul the omega up over one shoulder, raising him up and slam-dunking him back into the cold lake.

Spluttering as he came up, Levi punched him right in the gut, “Mother-fucker.”

“Oooph,” Erwin’s breath was temporarily knocked from him. Knowing the boy was unlikely to back down, Erwin made the decision for both of them, “Enough! I surrender.” He held his hands up in mock defeat. “I’m hungry anyway. I’m going to eat, and if you don’t come now, I’ll eat your share too.” Dignity forgotten when it was just the two of them alone, Erwin began to clumsily and noisily splash back to shore, pretending he was going to make good on his threat.

“You’ll regret it,” Levi warned him, wading in his wake and trying to keep up with the bigger man.

There was no one around for miles to see the two napping nude on the soft grass in the warm sun, bellies full after the veritable feast that Levi had somehow secreted away from the locked pantries. Waking up after an hour or so, Erwin smiled as he regarded the stretched out boy sleeping peacefully beside him. Levi had managed to grow since putting on some much needed weight, although he was still decidedly pre-pubescent.

Folding his arms behind his head and staring up at a few sparse clouds, Erwin grinned as he remembered their little fact-finding mission about the birds and the bees, drifting off to sleep as the memory replayed itself.

~~~~

“Alright then,” Levi plopped down heavily on the sofa beside him, crossing his legs and looking at him from bored-looking eyes, “show me this weird book.”

The two flicked through the pages together, taking in the basics of anatomy and biology. It was a straight-forward, matter-to-fact approach aimed- as the doctor had forewarned- at alphas with short-attention spans. Although it objectively covered important topics such as STDs and contraception, it didn’t go into any of the emotional or real-life aspects of growing up and relationships that the omega seemed particularly interested in.

“So betas fall in love and get married, but people like us get forced together by our biology?” Levi questioned after slowly reading the first chapter in silence.

Sighing, Erwin inclined his head, “That’s a simplified way of looking at it, yes. There isn’t a lot of mixing between alphas and omegas socially in case accidents happen, so most alpha and omega partners tend to leave falling in love until after their bonding occurs during a mating cycling when they are compelled to mate. A lot of cycles are coordinated between families; you could say it’s like arranging a marriage. Some wealthy alphas have more than one omega, but I wouldn’t have enough energy or material wealth to care for one spouse, let alone a whole harem.”

“But betas can only marry one person?”

The blonde nodded, “Yes, legally. So my father was a beta and he married my mother, and they had me.”

“Bet they were proud to have made an alpha,” the boy sniffed.

“Yes, it’s uncommon. But my father told me I would have been loved no matter what I was.”

“That’s nice,” Levi commented quietly.

“And your parents?” Erwin probed gently. He had a strong suspicion they were both dead, perhaps since Levi had been very young indeed.

My mom said she couldn’t work out who my father was.” Levi shrugged at the shocked expression Erwin was unable to hide on his face. “I told you she was a whore.” He spoke steadily, as though the profession was a totally average one. Maybe it was in the Underground city. “I would have probably ended up one too eventually if you hadn’t have found me.”

Speechless for a moment, Erwin tried to imagine the loss to humanity if _that_ had been this boy’s fate. “I thought you were kidding when you told me about your mother before. Have you ever-?” He started, unsure why he was asking.

Happily for the blonde, Levi shook his head, “No.”

In a hushed rush of air, Erwin let out a sigh he had been holding in as he waited for the answer, glad to hear that the boy had never been violated in such a terrible way.

“Men have tried though,” Levi commented. “And gangs kidnap boys like me and sell them. Lucky ones get sold to rich fucks on the Surface. Unlucky ugly ones get chained to a wall in a brothel and injected with heat stimulants.”

Appalled, Erwin found his hand had moved of its own volition to rest on Levi’s shoulder. “I had no idea. No wonder you were so scared when you came to up here without your clothes.”

The omega’s voice was quiet, and he looked down at where he was picking at a bit of loose skin on one of his fingers, “I thought you’d stolen me for yourself.”

“No,” Erwin whispered. “No, I would never do that.”

Rolling his eyes, Levi snorted, “I know that now, dumbass. I nearly pissed myself behind that chair when you came into the cell stinking of alpha hormones. I could hardly stand up with the stink, and I couldn’t get out from behind the chair at all. My limbs felt like they weighed a tonne.”

Looking back, Erwin remembered how unsteady Levi had been on his feet; how he had stayed behind the chair hissing and snarling at him, waves of fear emanating off him. At the time, he had assumed the omega was just challenging his authority, but now it appeared he had been genuinely paralysed by the strong scent marking. Erwin had never liked the fact that alphas could subjugate omegas with a powerful enough wave of scent, and hadn’t at all realised that was what had actually happened. Uneasily, he chewed the inside of his lip, “I might have been trying to come across as in control, and normally that type of scent marking is what is needed to impress and stabilise the behaviour of other alphas and betas. I didn’t consider that it might have a different effect on you. It was ignorant of me, and I apologise profusely.”

“Hmmmm,” Levi hmmmed gently, and with that, Erwin knew he was forgiven.

Turning the page and reading a short section describing the very thing he had done to Levi, Erwin cringed. The wholly natural response Levi had described was a biological imperative to reduce the risk of bodily harm by a much bigger male. Omegas would freeze up in response to strong scent marking, and the book implored to whoever was reading that the tactic was not misused by alphas looking to beat their mates for perceived misbehaviour or force them into have sex, arguing it might affect their omega’s delicate sensibilities. Holding back a snort, Erwin shook his head. What sort of man would do that? No real man at all. The paralysing effect could apparently also occur during oral sex, and there was a warning that it could also induce mini-heats in some omegas. By oral sex, he assumed that meant rimming; he wasn’t convinced he would want to give head to another man, even an omega. Perhaps especially an omega. It seemed demeaning to suck another man’s cock, particular if theirs was smaller. He couldn’t imagine getting on his knees for anyone.

“Do omegas mate with betas? Or each other?” Levi’s voice piped up, tearing him from the thought.

Pursing his lips, Erwin considered the question, “I’ve never heard of it happening. There probably wouldn’t be any children, and besides, omegas are seen as too valuable to ‘waste’ like that. I don’t think society would favour such unions. Alphas definitely marry beta women if they fall in love or want kids but can’t get an omega mate, but couples like that need regular sex to create children, and alphas are designed to have intense bouts of mating every three months or so, rather than get it on every night.”

A smirk crossed Levi’s young face, “So what you are saying is that betas are horny all the time and you guys can’t keep up.”

Feeling surprisingly touchy on the topic of his masculinity, Erwin frowned. “Our desires as alphas are more cyclical; more periodic,” he explained, rewording it to his liking. “They fluctuate with the likelihood of conception, and in omegas it abundantly clear when they are at peak fertility. When a rut is stimulated by the presence of an omega in heat, sex can occur up to twelve times a day for seven days. No beta could keep up with _that_. Although sex is still used to feel close and couple bond, it isn’t as necessary to maintain constant physical closeness in an alpha-omega relationship due to the existence of the mental bond between paired couples that betas don’t experience. As beta women don’t produce the pheromones that signal that they are ovulating, it’s difficult to feel aroused and perform at the right moments. Basically in order to conceive, a couple with a beta female need to have sex three or more times a week, whether or not they feel like doing it.”

“Boring,” deadpanned the boy. “What a waste of time. Why bother having sex at all?”

“It feels good, both physically and emotionally.”

“So why are alphas so fucking obsessed with knotting?”

“Probably because it feels good and makes them feel powerful, but during sex it’s not something under an alpha’s control, really. It’s more to do with the clamping down of the omega’s muscles on them.”

“So it doesn’t just inflate by itself? Why does it have to happen?”

Erwin paused, uncertain for a moment and blinded by the constant bombardment of questions. He was sure he had learned at least some of this in school and tried to wrack his brain. “No it won’t go up unless there’s a tight grip on the base. And as for why it’s important, omegas are unlikely to ovulate without the pain produced by knotting, which is a reflex only stimulated during a heat. Beta male penises can’t knot.” He gathered his thoughts. “Beta females ovulate spontaneously and unpredictably once a month, and as long as sperm in any form is available a pregnancy can result, so they can mate with either an alpha or beta man to reproduce. Success rates are pretty low though. Some couples need to try for years before popping out a baby.”

“And they have a totally different hole for that, don’t they?” Flicking through the book pages, Levi pointed at the basic diagram of a woman in cross-section. “Do they pee out of it too? Do they have heats?”

Finally, _something_ he actually did know. “Yes, no and no. They have three separate orifices, and they don’t have heat cycles; they bleed every month instead if they aren’t with child. Beta males don’t have rut cycles either.”

“So do I have a vagina? I’ve never noticed one. Will I start to bleed?” Levi shifted as though it would help him locate one.

Shaking his head, Erwin searched for a corresponding diagram of an omega, “You don’t have a separate opening, no, and you won’t bleed. You have a sheath inside you that starts in, and then parallels the rectum. There’s a muscular valve at its entrance that only allows anything to enter when penetration by a penis occurs _inwards_ , so faeces doesn’t accidentally get up there on its way out. Apparently it takes a certain angle, length and a high degree of stiffness to penetrate, which makes it almost impossible for beta males to find and actually enter with what they are endowed with. Alpha erections find their way in pretty naturally-apparently.” He added hastily.

“Are they so different?”

“Alpha penises are-“ Erwin made a shape with his hands, “-quite large when erect, and when the muscular ring at the base of the omega’s mating sheath contracts during heat, it causes blood to pool in the excess skin at the base and then it swells into a knot. When the muscular ring relaxes again, the knot goes down. Beta males penises don’t do that. They would probably just be forced out.”

Levi’s eyes glanced to Erwin’s crotch then to his eyes. The boy had seen Erwin’s tackle before, but clearly hadn’t thought too much about it. “And then they dump a load, right?”

“Uhhhh-“ taken aback at Levi’s crassness, Erwin wasn’t sure he’d ever been so flabbergasted. “Once the knot goes up then yes, the alpha ejaculates.”

How long does it take to go down?”

“Usually around half an hour to an hour and a half apparently.”

“What, and you get stuck together that long?” Levi looked scandalised. “How boring. And awkward. What do you talk about?”

“Well, during it, the mating sheath rhythmically contracts and stimulates ejaculation to continue occurring on a regular basis. It’ll do that every few minutes until the knot gets released. In between, I guess partners normally kiss, or pet each other or talk about quite mundane stuff. After that, there’s usually a couple of hours of respite before both partners feel compelled to mate again.”

“And that lasts for up to a week? That sounds awful. And messy.” The omega paused for a moment. “What about the bonding?”

“I think it happens during mating, but I don’t really understand it fully. Apparently you get a sense of what the other is feeling. It helps the couple feel close and stay faithful.”

 _At least on the omega’s side_ , Erwin thought to himself. There wasn’t an expectation for alphas to remain particularly monogamous.

“Sounds magicky,” Levi sounded unimpressed by the concept.

“Maybe.” It wasn’t really something Erwin believed in either. It did seem ‘magicky’ as Levi described, and was probably a myth. “Aside from its use for building feelings of love and tenderness between a couple, I know it has less good connotations as well- some alphas claim to use it to subjugate and control their omega’s behaviour.”

“I suppose I understand. I had a bond with my mom,” Levi mentioned off-handedly. “We could sense each other. When she had a client in with her she could use it to make me stay quiet in the cupboard so no-one would find me.”

Astonished and unsure whether such a case had ever been recorded before, Erwin’s mouth fell open slightly, “I’ve never heard of a beta being able to do it, especially with a child. Maybe you managed to establish it somehow with her and she learned how to use it.”

“Maybe. It was strong. Sometimes I could see what she could see, and she could tell if I was hungry. It meant I didn’t need to cry much.”

Eyes still wide and eyebrows raised, Erwin could only stutter, “T-that’s incredible. You must be mentally very strong to have been able to do that.” He would have loved a similar bond with his own father.

“How many people have you slept with?” Levi asked abruptly.

Stuttering again, Erwin smoothed a hand through his hair, “That’s a…..rather personal question.”

“You said I could ask you anything about what people do in bed,” The omega pointed out. He wasn’t one bit embarrassed about any of it.

“You’re right,” he sighed. _Having a sex life isn’t anything to be ashamed about_ , Erwin’s inner voice of reason tried to reassure himself. _He’s not judging you, he’s just curious, as all children are. And his mom was in the business of sex, so maybe he just feels differently about it to normal kids._

“I’ve been with only one woman,” the alpha admitted. “We were teenagers, and we considered getting married, but I loved her too much to subject her to being the spouse of a Survey Corps soldier. I ended it and I have no regrets.”

“Oh. That’s sad,” Levi commented, cheek squished where it was propped against his hand. “I’d have thought you’d have been with lots of people.”

“I spend a lot of time in my office,” he pointed out. “There’s a lot of admin I need to do if I’m to work my way up the ranks.”

“Yeah, you spend way too much time cooped up. You should go out with Mike and meet people. Someone out there is bound to be willing to sleep with you.”

Knowing that this was well meant, Erwin merely nodded, “Thank you, Levi.”

“Don’t you want an omega? To do knotting with? And the emotion bonding thing?”

“I want to remain a bachelor.”

Nodding hard, Levi agreed readily, “Me too. I don’t like the idea of someone being able to make me do stuff against my will. Society doesn’t respect omegas either way, but we get totally fucking looked down on once you end up tied to a fucking alpha.”

Closing his eyes at the idea, Erwin nodded his head, “When you do start having urges, please, please, please go to medical. Your heats can be controlled to occur at predictable times after that initial one, and if you don’t want a partner you can be isolated and sedated for the duration. You don’t want to get knocked up by accident.”

“No,” Levi shuddered. “What if some of my own spunk gets in the wrong place? Can I make myself pregnant?”

“To my knowledge, omegas don’t really produce many functioning sperm. And during intercourse itself, once the knot is up, they lose their erections and don’t ejaculate during orgasm. Orgasm is all internal.”

“What’s orgasm?”

“It’s uh-“ Erwin made a frustrated noise, not really believing that Levi didn’t know what it was, “-it’s like a reflex. Like hiccupping but it feels really good.”

Still looking confused at the frankly terrible explanation, Levi’s body language motioned for him to continue explaining.

“You must have had erections before?” He hesitated after asking the question, unsure if omegas _did_ actually get erections. Erwin himself had noticed them all his life, but had only really become interested in them when he hit twelve. Even then, nothing much had happened when he played with them until he was around fifteen, and he had probably shot blanks until he was at least sixteen.

“Yeah. So?” The omega shrugged. “What’s that got to do with nice hiccups?”

“Nothing,” Erwin jabbered. “But erections, they can feel good, right?”

“Dunno. They ache. I just leave ‘em alone till they go away.” He gave Erwin a curious look, “Why, what am I supposed to do?”

“Well, you can- uh- rub them?” Erwin offered, flushing red from his chest up to his hairline.

“Really? For how long?”

Was it getting terribly warm and stuffy in his office all of a sudden, or was it just his imagination? “Until you orgasm.”

“Why? What’s the point?”

Erwin plucked at his shirt to get some air moving near to his skin, “It feels good. And it gets rid of stress.”

“So does exercise.”

He wasn’t really sure why he was giving masturbatory advice to the omega. For all he knew, they pleasured themselves in entirely different ways, if at all. Did their external genitals even give them pleasure? He was so ignorant, and wished that his father had been around when he was Levi’s age to answer all these types of questions. Being a beta man, he may not have been able to answer them all himself, but Erwin was sure that his father would have gone out of his way to find out somehow and report back to him. The good man would never have shied away from any topic, no matter how unseemly or private society at large or the church deemed it to be. Erwin tried his best to consider what answer his father would give Levi. 

“Yes but masturbation leads to orgasm, which produces semen for reproduction," the blonde explained. 

“Oh,” Levi looked genuinely astonished at this. “I thought cum was the same as piss.”

“No, not at all.” He wasn’t sure why he expected Levi to know this. “Very different processes. Piss is waste water. Semen is white and more viscous, and nowhere near the same volume. The only thing they have in common is where they exit the body from. Trust me, you wouldn’t want half a litre of urine being deposited inside you during sex.”

Puffing out his cheeks and exhaling, Levi shrugged again, “I thought that was how it worked.”

“Hah!” The laugh forcibly barked itself out of him, earning the blonde a glare. “I’m sorry, that’s just so-“ he blinked, “-innocent?”

“Go fuck yourself,” Levi suggested before once again going off at a tangent. “A knot sounds sore. How big is it?”

Considering what he was able to stimulate himself to when in the mood to play with his own, Erwin put his fingers together in the shape of a small football, “About that big,”

“Nope.” Levi crossed his arms and shook his head violently. “No way am I _ever_ doing that. Something would rupture, or my pelvis would split in two.”

“Apparently it is a bit sore just at the start, and that stimulates ovulation. After that, omegas report it feels pretty good.”

“Gross. So outside of heats, do knots happen during sex?”

“I don’t know. I don’t think so, but maybe there’s an element of voluntary control over it? I don’t know any adult omegas to ask.”

Tilting his head, Levi narrowed his eyes in confusion, “Why not?”

“Uh-“ Feeling astonishment at Levi’s social ignorance, Erwin just shook his head. “It’s not the done thing for an alpha and omega to be too chummy. For the omega, it might tarnish their reputation to have an alpha as a friend. People would presume their relationship was more than just friendship.”

Back straightening, Levi made as if to move away. “So, should we not be friends?”

Looking at Levi’s downcast expression at his words, Erwin felt his heart tug hard in his chest, “No. We should absolutely be friends. We’re different.”

At the reassurance, Levi relaxed again and leaned back towards him.

 _We are different_ , Erwin tried to convince himself. He didn’t want to lose his little companion who had so unexpectedly and smoothly entered his life.

_We are different._

~~~~

He awoke to the sound of splashing. Levi was waist-deep in the lake, lifting a big, angry-looking fish out of the water and dragging it to shore, unhooking it and adding it to a pile of others he had already caught.

“Afternoon, sleeping beauty,” Levi deadpanned at him as the fish behind him slopped about noisily on the wet sand. “You were dead to the fucking world for hours.” The sun had moved far across the sky and he felt refreshed and invigorated. It had been a good nap. “We should probably head back,” the omega suggested as he began drying himself off.

Stretching out his limbs and feeling terribly content, Erwin was loathe to move. “Do we have to?”

Scoffing, Levi chucked the now slightly-damp towel onto the blonde’s belly, “Well, what would you suggest?”

He folded his arms behind his head and inhaled deeply, “I don’t know. We could build a house here, make this our home. We could live here and do this every day.”

 _Wouldn’t that be nice?_ He thought to himself as he looked up at his friend; at the only person who really mattered in the entire world.

“Sounds nice. But dull.” Levi conceded. He held out a hand, “Come on, let’s go before you start dedicating your heart to building a shitty log-” Unexpectedly, Levi’s voice dropped an octave, “-cabin.” He froze and looked down at Erwin. “What the-?”

Grinning, Erwin clapped his hand into the outstretched one and allowed himself to be pulled up before shaking the teen’s hand, “Congratulations, Levi. Your voice is breaking.”

“I don’t know if I-“ Levi stopped, looking annoyed at the way the pitch rose and fell involuntarily. “Fuck, I sound stupid.”

Running his other hand through his now dry hair, Erwin laughed, “It’ll do that for a while. One day you’ll wake up and it will stop going high.” Pulling on a pair of pants, he remarked, “You have a nice timbre. Much deeper than I thought you’d have. It suits you.”

Boots squeaking as he walked across the wet sand and away through the trees, Levi hoisted the duffel bag full of fish onto his back, their damp weight showing the world how hard he’d worked to put food on the table that day. The kitchen staff would be thrilled at having meat to cook for a change.

Standing at the riverbank, Erwin gave one last look at the peaceful lake before following the omega back home.


End file.
